NC0047597_Application_20151028

CITY OF DURHAM
IEPARTMENT OF WATER MANAGEMENT
)1 CITY HALL PLAZA • DURHAM, NC 27701
r '--319-560-4381•FAX
■■
919-560-4479
www.durhamnc.gov
1869
City OF MEDIONE
October 28, 2015
NCDEQ/ DWQ
Attn: NPDES Unit
1621 Mail Service Center
Raleigh, North Carolina 27699-1621
RECEIVEDIDENRIDWR
OCT 3 0 2015
Water Quaiity
Permitting Section
Subject: South Durham Water Reclamation Facility
NPDES Permit NCO047597
Permit Renewal Application
Dear Mr. Belnick,
Administration
919-560-4381
Customer Billing Services
919-560-4412
Laboratory Services
919-560-4386
Plant Maintenance
919-560-4388
Regulatory Compliance
919-560-4381
Utility Engineering
919-560-4381
Wastewater Treatment
North - 919-560-4384
South- 919-560-4386
Water Supply & Treatment
Williams - 919-560-4348
Brown - 919-560-4362
Water & Sewer Maintenance
919-560-4344
The City of Durham owns and operates the South Durham Water Reclamation Facility,
NPDES Permit NC0047597. The City of Durham requests the renewal of this operating
permit for the facility.
The facility is currently operating under a permit originally issued in April, 2011 and
modified in January, 2013. Since the issuance of this permit, the facility has undergone the
following changes.
• Anew caustic feed building was constructed to replace a poorly functioning one.
It includes a new 10,000 gallon storage tank.
• The air flow to the aeration basins was improved and the process flow short-
circuiting issues were corrected.
• The alum feed building was reconfigured, with more pumps dedicated to
specific feed points.
• The reclaimed water system within the facility will have sodium hypochlorite
added for dual disinfection (also UV). This will enable SDWRF to distribute reuse
water in bulk to customers for non -potable use. Training and other activities will
be modeled on the successful NDWRF Bulk Reclaimed operations system.
(anticipated date on-line — lst quarter 2016)
• A carbon feed facility is under construction to improve nitrogen removal.
(anticipated date on-line —151 quarter 2016)
• A Kruger Inc. designed Side Stream Treatment Facility was installed by
retrofitting/repurposing an abandoned aerobic digester. This process is
expected to remove up to 90% of the ammonia from the belt press filtrate.
Durham — Where Great Things Happen

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Page -2-
SDWRF Permit Renewal Application
All of the improvements noted were part of a construction project that began in May, 2014.
It is anticipated that the entire project will be completed in early 2016.
The Permit Renewal Application Packet includes one original and two copies of the
following documents:
• A cover letter signed by the Director of the Department of Water Management.
• The completed NPDES Form 2A Application Overview.
- Information in Part D - Expanded Effluent Testing Data, is supplemented
with copies of the results of three Priority Pollutant Analyses.
- In lieu of filling out Part E -Toxicity Testing Data, the results of all of the
quarterly tests are included. Two additional second species (Fathead
Minnow) toxicity test results will be sent in as they are completed. They are
scheduled for the week of November 2nd and the week of December 7m
• A narrative description of the sludge management plan for the facility.
• A narrative description of plans to decrease the amount of inflow and infiltration
in the collection system.
• Various facility related documents, maps and photos.
If you need any additional information, please contact Charles Cocker, Superintendent/ORC
of the South Durham WRF at 919-560-4386 or by email at [e-mail].
Sincerely,
Donald F. Greeley, P.E., PLS
Director
C: Vicki Westbrook, Assistant Director, Department of Water Management
Charles Cocker, Superintendent, South Durham WRF
Reginald Hicks, Environmental Compliance Officer, Water Management
Durham — Where Great Things Happen

FACILITY NAME AND PERMIT NUMBER:
PERMIT ACTION REQUESTED:
RIVER BASIN:
/'*A
r400IN
South Durham WRF, NCO047597
FORM
2A FMPDMM7 � RM 2A
NPDES
APPLICATION OVERVIEW
Renewal
Cape Fear
Form 2A has been developed in a modular format and consists of a "Basic Application Information" packet
and a "Supplemental Application Information" packet. The Basic Application Information packet is divided
into two parts. All applicants must complete Parts A and C. Applicants with a design flow greater than or
equal to 0.1 mgd must also complete Part B. Some applicants must also complete the Supplemental
Application Information packet. The following items explain which parts of Form 2A you must complete.
BASIC APPLICATION INFORMATION:
A. Basic Application Information for all Applicants. All applicants must complete questions A.1 through A.8. A treatment works
that discharges effluent to surface waters of the United States must also answer questions A.9 through A.12.
B. Additional Application Information for Applicants with a Design Flow z 0.1 mgd. All treatment works that have design flows
greater than or equal to 0.1 million gallons per day must complete questions BA through B.6RECEIVEDIDENRIDWR
C. Certification. All applicants must complete Part C (Certification).
op 3G 2015
SUPPLEMENTAL APPLICATION INFORMATION: WFf
Per.,.,.,. -
D. Expanded Effluent Testing Data. A treatment works that discharges effluent to surface waters of the United States and meets
one or more of the following criteria must complete Part D (Expanded Effluent Testing Data):
1. Has a design flow rate greater than or equal to 1 mgd,
.2. Is required to have a pretreatment program (or has one in place), or
3. Is otherwise required by the. permitting authority to provide the information.
E. Toxicity Testing Data. A treatment works that meets one or more of the following criteria must complete Part E (Toxicity Testing
Data):
1. Has a design flow rate greater than or equal to 1 mgd,
2. Is required to have a pretreatment program (or has one in place), or
3. Is otherwise required by the permitting authority to submit results of toxicity testing.
F. Industrial User Discharges and RCRA/CERCLA Wastes. A treatment works that accepts process wastewater from any
significant industrial users (SIUs) or receives RCRA or CERCLA wastes must complete Part F (Industrial User Discharges
and RCRAICERCLA Wastes). SIUs are defined as:
1. All industrial users subject to Categorical Pretreatment Standards under 40 Code of Federal Regulations (CFR) 403.6 and
40 CFR Chapter 1, Subchapter N (see instructions); and
2. Any other industrial user that:
a. Discharges an average of 25,000 gallons per day or more of process wastewater to the treatment works (with certain
exclusions); or
b. Contributes a process wastestream that makes up 5 percent or more of the average dry weather hydraulic or organic
capacity of the treatment plant; or
C. Is designated as an SIU by the control authority.
G. Combined Sewer Systems. A treatment works that has a combined sewer system must complete Part G (Combined Sewer
Systems).
ALL APPLICANTS MUST COMPLETE PART C (CERTIFICATION)
EPA Form 3510-2A (Rev. 1-99). Replaces EPA forms 7550-6 & 7550-22.
Page 1 of 22

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FACILITY NAME AND PERMIT NUMBER:
PERMIT ACTION REQUESTED:
RIVER BASIN:
South Durham WRF, NCO047597
Renewal
Cape Fear
BASIC APPLICATION INFORMATION
PART A. BASIC APPLICATION INFORMATION FOR ALL APPLICANTS:
All treatment works must complete questions A.1 through A.8 of this Basic Application Information Packet.
A.I. Facility Information.
Facility Name South Durham Water Reclamation Facility
Mailing Address 6605 Farrington Road
Chapel Hill, NC 27517
Contact Person Donald Greeley
Title Director — Department of Water Management
Telephone Number [phone]
Facility Address 6605 Farrington Road
(not P.O. Box) Chapel Hill, NC 27517
A.2. Applicant Information. If the applicant is different from the above, provide the following:
Applicant Name
Mailing Address
Contact Person
Title
Telephone Number ( )
Is the applicant the owner or operator (or both) of the treatment works?
❑ owner ® operator
Indicate whether correspondence regarding this permit should be directed to the facility or the applicant.
❑ facility ® applicant
A.3. Existing Environmental Permits. Provide the permit number of any existing environmental permits that have been issued to the treatment works
(include state -issued permits).
NPDES NCO047597 PSD
UIC Other STORMWATER NPDES NCG110082
RCRA Other LAND APPLICATION (503) W00003504
A.4. Collection System Information. Provide information on municipalities and areas served by the facility. Provide the name and population of each
entity and, if known, provide information on the type of collection system (combined vs. separate) and its ownership (municipal, private, etc.).
Name Population Served Type of Collection System Ownership
City of Durham 146,000 sanitary sewer City of Durham
Total population served 146.000
EPA Form 3510-2A (Rev. 1-99). Replaces EPA forms 7550-6 & 7550-22.
Page 2 of 22

FACILITY NAME AND PERMIT NUMBER: PERMIT ACTION REQUESTED: RIVER BASIN:
South Durham WRF, NCO047597 I Renewal I Cape Fear
A.5. Indian Country.
a. Is the treatment works located in Indian Country?
❑ Yes ® No
b. Does the treatment works discharge to a receiving water that is either in Indian Country or that is upstream from (and eventually flows
through)Indian Country?
❑ Yes ® No
A.6. Flow. Indicate the design flow rate of the treatment plant (i.e., the wastewater flow rate that the plant was built to handle). Also provide the
average daily flow rate and maximum daily flow rate for each of the last three years. Each year's data must be based on a 12-month time period
with the 121h month of "this year" occurring no more than three months prior to this application submittal.
a. Design flow rate 20.0 mgd
b. Annual average daily flow rate
Two Years Apo Last Year This Year
8.85
C. Maximum daily flow rate 26.54 27.44 22.76
A.7. Collection System. Indicate the type(s) of collection system(s) used by the treatment plant. Check all that apply. Also estimate the percent
contribution (by miles) of each.
® Separate sanitary sewer 100
❑ Combined storm and sanitary sewer
A.8. Discharges and Other Disposal Methods.
a. Does the treatment works discharge effluent to waters of the U.S.? ® Yes ❑ No
If yes, list how many of each of the following types of discharge points the treatment works uses:
i. Discharges of treated effluent 1
it. Discharges of untreated or partially treated effluent
W. Combined sewer overflow points
IV. Constructed emergency overflows (prior to the headworks)
V. Other
b. Does the treatment works discharge effluent to basins, ponds, or other surface impoundments
that do not have outlets for discharge to waters of the U.S.? ❑ Yes ® No
If yes, provide the following for each surface impoundment:
Location:
Annual average daily volume discharge to surface impoundment(s)
Is discharge ❑ continuous or ❑ intermittent?
C. Does the treatment works land -apply treated wastewater?
If yes, provide the following for each land application site:
Location:
Number of acres:
❑ Yes
Annual average daily volume applied to site: mgd
Is land application ❑ continuous or ❑ intermittent?
d. Does the treatment works discharge or transport treated or untreated wastewater to another
treatment works? ❑ Yes
mgd
® No
M
EPA Form 3510-2A (Rev. 1-99). Replaces EPA forms 7550-6 8 7550-22. Page 3 of 22

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FACILITY NAME AND PERMIT NUMBER:
PERMIT ACTION REQUESTED:
RIVER BASIN:
South Durham WRF, NCO047597
Renewal
Cape Fear
If yes, describe the mean(s) by which the wastewater from the treatment works is discharged or transported to the other treatment works
(e.g., lank truck, pipe).
If transport is by a party other than the applicant, provide:
Transporter Name
Mailing Address
Contact Person
Title
Telephone Number ( 1
For each treatment works that receives this discharci provide the following:
Name
Mailing Address
Contact Person
Title
Telephone Number ( 1
If known, provide the NPDES permit number of the treatment works that receives this discharge
Provide the average daily Flow rate from the treatment works into the receiving facility.
mgd
e. Does the treatment works discharge or dispose of its wastewater in a manner not included
in A.8. through A.8.d above (e.g., underground percolation, well injection): ❑ Yes
® No
If yes, provide the following for each disposal method:
Description of method (including location and size of site(s) A applicable):
Annual daily volume disposed by this method:
Is disposal through this method ❑ continuous or ❑ intermittent?
EPA Form 3510-2A (Rev. 1-99). Replaces EPA forms 7550-6 & 7550-22.
Page 4 of 22

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FACILITY NAME AND PERMIT NUMBER: PERMIT ACTION REQUESTED: RIVER BASIN:
South Durham WRF, NCO047597 Renewal Cape Fear
WASTEWATER DISCHARGES:
If you answered "Yes" to question A.8.a, complete questions A.9 through A.12 once for each outfall (including bypass points) through
which effluent is discharged. Do not include Information on combined sewer overflows in this section. If you answered "No" to question
A.B.a, go to Part B, "Additional Application Information for Applicants with a Design Flow Greater than or Equal to 0.1 mgd."
A.9. Description of Outfall.
a. Outfall number 001
b. Location Durham
(City or town, if applicable)
(County)
(Latitude)
C. Distance from shore (if applicable)
d. Depth below surface (if applicable)
e. Average daily flow rate
f. Does this outfall have either an intermittent or a periodic discharge?
If yes, provide the following information:
Number f times per year discharge occurs:
Average duration of each discharge:
Average flow per discharge:
Months in which discharge occurs:
g. Is outfall equipped with a diffuser?
(Zip Code)
(State)
(Longitude)
ft.
ft.
9.10 mgd
❑ Yes ® No (goto A.9.g.)
❑ Yes ® No
A.10. Description of Receiving Waters.
a. Name of receiving water unnamed tributary to New Hope Creek
b. Name of watershed (if known) New Hope
United States Soil Conservation Service 14-digit watershed code (if known):
C. Name of State Management/River Basin (if known): Cape Fear
United States Geological Survey 8-digit hydrologic cataloging unit code (if known):
d. Critical low flow of receiving stream (if applicable)
mgd
03020101
acute 12.9 cis chronic 7Q10+6.1 cis
e. Total hardness of receiving stream at critical low flow (if applicable): mgll of CaCO3
EPA Forth 3510-2A (Rev. 1-99). Replaces EPA forms 7550-6 & 7550-22.
Page 5 of 22

i.
FACILITY NAME AND PERMIT NUMBER:
PERMIT ACTION REQUESTED:
RIVER BASIN:
South Durham WRF, NCO047597
Renewal
Cape Fear
A.11. Description of Treatment
a. What level of treatment are provided? Check all that apply.
® Primary ® Secondary
® Advanced ❑ Other. Describe:
b. Indicate the following removal rates (as applicable):
Design BOD5 removal or Design CBOD5 removal 98 %
Design SS removal 97 %
Design P removal 90 %
Design N removal 94% as NH3 %
Other %
C. What type of disinfection is used for the effluent from this outfall? If disinfection varies by season, please describe:
Ultraviolet Light
If disinfection is by chlorination is dechlorination used for this outfall? ❑ Yes ❑ No
Does the treatment plant have post aeration? ® Yes ❑ No
A.12. Effluent Testing Information. All Applicants that discharge to waters of the US must provide effluent testing data for the following
parameters. Provide the indicated effluent testing required by the permitting authority for each outfall through which effluent is
discharged. Do not include information on combined sewer overflows In this section. All Information reported must be based on data
collected through analysis conducted using 40 CFR Part 136 methods. In addition, this data must comply with QA/QC requirements of
40 CFR Part 136 and other appropriate QA/QC requirements for standard methods for analytes not addressed by 40 CFR Part 136. At a
minimum, effluent testing data must be based on at least three samples and must be no more than four and one-half years apart.
Outfall number: 001
MAXIMUM DAILY VALUE
AVERAGE DAILY VALUE
PARAMETER
Value
Units
Value
Units
Number of Samples
pH (Minimum)
6.5
S.U.
pH (Maximum)
7.3
S.U.
Flow Rate
17.83
MGD
8.70
MGD
365
Temperature (Winter)
22
C
16
C
154
Temperature (Summer)
29
C
24
C
211
2' For pH please report a minimum and a maximum
daily value
MAXIMUM DAILY
AVERAGE DAILY DISCHARGE
POLLUTANT
DISCHARGE
ANALYTICAL
ML/MDL
Conc.
Units
Conc.
Units
Number of
METHOD
Samples
CONVENTIONAL AND NON CONVENTIONAL COMPOUNDS
BIOCHEMICAL OXYGEN
SODS
1s
M /I
2.1
M ll
251
SM 5210 B
NA
DEMAND (Report one)
CBOD5
FECAL COLIFORM
>2419.6
Mpn/100
17.0
Mpn/100
251
SM 9222 D
NA
TOTAL SUSPENDED SOLIDS (TSS)
10.2
Mg/I
<2.5
Mg/I
251
SM 2450 D
NA
END OF PART A.
REFER TO THE APPLICATION OVERVIEW (PAGE 1) TO DETERMINE WHICH OTHER PARTS
OF FORM 2A YOU MUST COMPLETE
EPA For 3510-2A (Rev. 1-99). Replaces EPA fors 7550-6 & 7550-22.
Page G of 22

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FACILITY NAME AND PERMIT NUMBER:
PERMIT ACTION REQUESTED:
RIVER BASIN:
South Durham WRF, NCO047597
Renewal
Cape Fear
BASIC APPLICATION INFORMATION
PART B. ADDITIONAL APPLICATION INFORMATION FOR APPLICANTS WITH A DESIGN FLOW GREATER THAN OR
EQUAL TO 0.1 MGD (100,000 gallons per day).
All applicants with a design Flow rate z 0.1 mgd must answer questions B.1 through B.6. All others go to Part C (Certification).
B.I. Inflow and Infiltration. Estimate the average number of gallons per day that Flow into the treatment works from inflow and/or infiltration.
2,000,000 gpd
Briefly explain any steps underway or planned to minimize inflow and infiltration.
Collection system flow monitoring. In-house and contract CCTV inspection. In-house and contract Pressure tesfing and grouting.
Contract CIPP lining. In-house and contract point repairs, implementing our CMOM Program I & I assessment will start in 2016
B.2. Topographic Map. Attach to this application a topographic map of the area extending at least one mile beyond facility, property boundaries. This
map must show the outline of the facility and the following information. (You may submit more than one map if one map does not show the entire
area.)
a. The area surrounding the treatment plant, including all unit processes.
b. The major pipes or other structures through which wastewater enters the treatment works and the pipes or other structures through which
treated wastewater is discharged from the treatment plant. Include outfalls from bypass piping, if applicable.
c. Each well where wastewater from the treatment plant is injected underground.
d. Wells, springs, other surface water bodies, and drinking water wells that are: 1) within % mile of the property boundaries of the treatment
works, and 2) listed in public record or otherwise known to the applicant.
e. Any areas where the sewage sludge produced by the treatment works is stored, treated, or disposed.
I. If the treatment works receives waste that is classified as hazardous under the Resource Conservation and Recovery Act (RCRA) by truck, rail,
or special pipe, show on the map where the hazardous waste enters the treatment works and where it is treated, stored, and/or disposed.
B.3. Process Flow Diagram or Schematic. Provide a diagram showing the processes of the treatment plant, including all bypass piping and all
backup power sources or redundancy in the system. Also provide a water balance showing all treatment units, including disinfection (e.g.,
chlorination and dechlodnation). The water balance must show daily average flow rates at influent and discharge points and approximate daily flow
rates between treatment units. Include a brief narrative description of the diagram.
B.4. Operation/Maintenance Performed by Contractor(s).
Are any operational or maintenance aspects (related to wastewater treatment and effluent quality) of the treatment works the responsibility of a
contractor? ® Yes ® No
If yes, list the name, address, telephone number, and status of each contractor and describe the contractor's responsibilities (attach additional
pages if necessary).
Name: Synagro
Mailing Address: 284 Boger Road
Mocksville. NC 27028
Telephone Number. [phone]
Responsibilities of Contractor. Land application of biosolids
B.5. Scheduled improvements and Schedules of Implementation. Provide information on any uncompleted implementation schedule or
uncompleted plans for improvements that will affect the wastewater treatment, effluent quality, or design capacity of the treatment works. If the
treatment works has several different implementation schedules or is planning several improvements, submit separate responses to question B.5
for each. (If none, go to question B.6.)
a. List the outfall number (assigned in question A.9) for each outfall that is covered by this implementation schedule.
001
b. Indicate whether the planned improvements or implementation schedule are required by local, State, or Federal agencies.
❑ Yes ® No
EPA Form 3510-2A (Rev. 1-99). Replaces EPA forms 7550-6 & 7550-22.
Page 7 of 22

FACILITY NAME AND PERMIT NUMBER:
PERMIT ACTION REQUESTED:
RIVER BASIN:
South Durham WRF, NCO047597
Renewal
Cape Fear
C. If the answer to B.S.b is'Yes,' briefly describe, including new maximum daily inflow rate (if applicable).
d. Provide dates imposed by any compliance schedule or any actual dates of completion for the implementation steps listed below, as
applicable. For Improvements planned independently of local, State, or Federal agencies, indicate planned or actual completion dales, as
applicable. Indicate dates as accurately as possible.
Schedule Actual Completion
Implementation Stage MM/DD/YYYY MMIDDIYYYY
- Begin Construction 10/01/2017 / /
- End Construction 10/01/2020 / /
- Begin Discharge I l l I
- Attain Operational Level I / I /
e. Have appropriate permits/clearances concerning other Federal/State requirements been obtained? ❑ Yes ❑ No
Describe briefly: New Preliminary Treatment Facility Final Clarifier UV Facility, replace filter media replace Aeration Basin diffusers
and diffuser grids
B.6. EFFLUENT TESTING DATA (GREATER THAN 0.1 MGD ONLY).
Applicants that discharge to waters of the US must provide effluent testing data for the following parameters. Provide the Indicated
effluent testing required by the permitting authority for each outfall through which effluent is discharged. Do not include Information
on combine sewer overflows in this section. All Information reported must be based on data collected through analysis conducted
using 40 CFR Part 136 methods. In addition, this data must comply with QAIQC requirements of 40 CFR Part 136 and other appropriate
QA/QC requirements for standard methods for analytes not addressed by 40 CFR Part 136. At a minimum effluent testing data must be
based on at least three pollutant scans and must be no more than four and on -half years old.
Outfall Number: 001
MAXIMUM DAILY
AVERAGE DAILY DISCHARGE
POLLUTANT
DISCHARGE
ANALYTICAL
MLIMDL
Conc.
Units
Con,.
Units
Number of
METHOD
Samples
CONVENTIONAL AND NON CONVENTIONAL COMPOUNDS
AMMONIA (as N)
3.10
Mgn
0.20
Mgn
251
SM 4500D
0.01
CHLORINE (TOTAL
14
Ugll
12.3
Ugll
3
RESIDUAL, TRC)
DISSOLVED OXYGEN
9.8
Mgn
8.1
Mgn
365
TOTAL KJELDAHL
2.83
Mgn
1.23
Mgn
52
EPA 351.2
0.12
NITROGEN (TKN)
NITRATE PLUS NITRITE
11.70
Mgll
7.53
Mg/I
52
EPA 300.0
0.01
NITROGEN
OIL and GREASE
<2.4
Mg/I
0
Mgn
3
EPA 1664B
2.40
PHOSPHORUS (Total)
1.86
Mgfl
0.38
Mgn
52
0.02
TOTAL DISSOLVED SOLIDS
(TDS)
OTHER
END OF PART B.
REFER TO THE APPLICATION OVERVIEW (PAGE 1) TO DETERMINE WHICH OTHER PARTS
OF FORM 2A YOU MUST COMPLETE
EPA Form 3510-2A (Rev. 1-99). Replaces EPA forms 7550-6 & 7550-22.
Page 8 of 22

Aft.
FACILITY NAME AND PERMIT NUMBER:
PERMIT ACTION REQUESTED:
RIVER BASIN:
South Durham WRF, NCO047597
Renewal
Cape Fear
BASIC APPLICATION INFORMATION
PART C. CERTIFICATION
All applicants must complete the Certification Section. Refer to instructions to determine who is an officer for the purposes of this
certification. All applicants must complete all applicable sections of Form 2A, as explained in the Application Overview. Indicate below which
parts of Form 2A you have completed and are submitting. By signing this certification statement applicants confirm that they have reviewed
Form 2A and have completed all sections that apply to the facility for which this application is submitted.
Indicate which parts of Form 2A you have completed and are submitting:
® Basic Applical en Information packet Supplemental Application Information packet:
® Part D (Expanded Effluent Testing Data)
® Part E (Toxicity Testing: Bio monitoring Data)
® Part F (Industrial User Discharges and RCRA/CERCLA Wastes)
❑ Part G (Combined Sewer Systems)
ALL APPLICANTS MUST COMPLETE THE FOLLOWING CERTIFICATION.
I certify under penally of law that this document and all attachments were prepared under my direction or supervision in accordance with a system
designed to assure that qualified personnel property gather and evaluate the information submitted. Based on my inquiry of the person or persons who
manage the system or those persons directly responsible for gathering the information, the information is, to the best of my knowledge and belief, true,
accurate, and complete. I am aware that there are significant penalties for submitting false information, including the possibility of fine and imprisonment
for knowing violations.
Name and official title Donald Greeley - Director- Department of Water Management
Signature
C
Telephone number [phone]
Date signed/S
Upon request of the permitting authority, you must submit any other information necessary to assure wastewater treatment practices at the treatment
works or identify appropriate permitting requirements.
n
SEND COMPLETED FORMS TO:
NCDENR/ DWQ
Attn: NPDES Unit
1617 Mail Service Center
Raleigh, North Carolina 27699-1617
EPA Fonn 3510-2A (Rev. 1-99). Replaces EPA forms 7550E & 7550-22. Page 9 of 22

r%
FACILITY NAME AND PERMIT NUMBER:
South Durham WRF, NCO047597
PERMIT ACTION REQUESTED:
Renewal
RIVER BASIN:
Cape Fear
SUPPLEMENTAL APPLICATION INFORMATION
PART D. EXPANDED EFFLUENT TESTING DATA
Refer to the directions on the cover page to determine whether this section applies to the treatment works.
Effluent Testing: 1.0 regal and Pretreatment Works. If the treatment works has a design Flow greater than or equal to 1.0 mgd or it has (or is required
to have) a pretreatment program, or is otherwise required by the permitting authority to provide the data, then provide effluent testing data for the following
pollutants. Provide the indicated effluent testing information and any other information required by the permitting authority for each outfall through which
effluent Is discharged. Do not include information on combined sewer overflows in this section. All information reported must be based on data collected
through analyses conducted using 40 CFR Part 136 methods. In addition, these data must comply with QA/QC requirements of 40 CFR Part 136 and
other appropriate QA/QC requirements for standard methods for analyles not addressed by 40 CFR Part 136. Indicate in the blank rows provided below
any data you may have on pollutants not specifically listed in this form. At a minimum, effluent testing data must be based on at least three pollutant
scans and must be no more than four and one-half years old.
Outfall number. 001 (Complete once for each outfall discharging effluent to waters of the United States.)
POLLUTANT
MAXIMUM DAILY DISCHARGE
AVERAGE DAILY DISCHARGE
ANALYTICAL
METHOD
ML/MDL
Conc.
Units
Mass
Units
Conc.
Units
Mass
Units
Number
of
Samples
METALS (TOTAL RECOVERABLE), CYANIDE, PHENOLS, AND HARDNESS.
ANTIMONY
0.685
Ugll
0,456
Ugll
3
EPA 6020A
0.220
ARSENIC
<2.80
Ugn
0
Ugll
3
EPA 6010C
2.800
BERYLLIUM
<0.100
Ugn
0
Ugll
3
EPA 6010C
0.100
CADMIUM
4.360
Ugll
0
Ugll
3
EPA 6010C
0.360
CHROMIUM
1.48
Ugll
0.493
Ugll
3
EPA 6020A
0.450
COPPER
2.63
Ugll
1.94
Ugll
3
EPA 6020A
0.100
LEAD
<1.90
Ugn
0
Ugll
3
EPA 6010C
1.900
MERCURY
3.88
ngn
1.05
ngll
29
EPA 1631E
0.50
NICKEL
2.75
Ugll
2.51
Ugn
3
EPA 6010C
1.80
SELENIUM
<2.70
Ugll
0
Ugll
3
EPA 6010C
2.700
SILVER
<0.100
Ugll
0
UgN
3
EPA 6020A
0.100
THALLIUM
0.266
Ugll
0.089
Ugli
3
EPA 6020A
0.110
ZINC
60.9
Ugll
48.0
Ugn
3
EPA 6010C
3.80
CYANIDE
<.0037
Mgll
0
MgFl
3
EPA 335A
0.0037
TOTAL PHENOLIC
COMPOUNDS
<0.02
Mgll
0
Mg9
3
EPA 420.1
0.020
HARDNESS (as CaCO3)
69
Mgll
1 _r_1
61
MgFl
3
SM 23408-
1997
0.018
Use this space (or a separate sheet) to provide information on other metals requested by the permit writer
EPA Form 3510-2A (Rev. 1-99). Replaces EPA forms 7550-6 R 7550-22.
Page 10 of 22

/►,
/^
FACILITY NAME AND PERMIT NUMBER:
South Durham WRF, NCO047597
PERMIT ACTION REQUESTED:
Renewal
RIVER BASIN:
Cape Fear
Outfall number. 001 (Complete once for each outfall discharging effluent to waters of the United States.)
POLLUTANT
MAXIMUM DAILY DISCHARGE
AVERAGE DAILY DISCHARGE
ANALYTICAL
METHOD
MLIMDL
Conc.
Units
Mass
Units
Conic.
Units
Mass
Units
Number
of
Samples
1'1.1
TRICHLOROETHANE
<0.12
Ugll
0
Ugll
3
EPA 624
0.12
RIC
TRICHLOROETHANE
40.14
Ugll
0
Ugll
3
EPA 624
0.14
TRICHLOROETHYLENE
<0.15
Ugll
0
Ugll
3
EPA 624
0.15
VINYL CHLORIDE
<0.32
Ugll
0
Ugll
3
EPA 624
0.32
Use this space (or a separate sheet) to provide information on other volatle organic compounds requested by the permit writer
ACID -EXTRACTABLE COMPOUNDS
P-CHLORO-M-CRESOL
2-CHLOROPHENOL
<1.2
Ugll
0
Ugll
3
EPA 625
1.2
2,4-DICHLOROPHENOL
2,4-DIMETHYLPHENOL
<1.3
Ugll
0
Ugn
3
EPA 625
1.3
4,6-DIN ITRO-O-CRESOL
2,4-DINITROPHENOL
<2.6
Ugll
0
Ugll
3
EPA 625
2.6
2-NITROPHENOL
<1.1
Ug0
0
Ugll
3
EPA 625
1.1
4-NITROPHENOL
<2.0
Ugll
0
Ugll
3
EPA 625
2.0
PENTACHLOROPHENOL
<1.8
Ugll
0
Ugll
3
EPA 625
1.8
PHENOL
<1A
Ugll
0
Ugll
3
EPA 625
1.4
TRIC
TRIOHLOROPHENOL
<1.1
Ugll
0
Ugll
3
EPA 625
1.1
Use this space (or a separate sheet) to provide information on other acid -extractable compounds requested by the permit writer
BASE -NEUTRAL COMPOUNDS
ACENAPHTHENE
<11A
Ugn
0
Ugn
3
EPA 625
1.4
ACENAPHTHYLENE
0.2
Ugll
0
Ugll
3
EPA 625
1.2
ANTHRACENE
<11.6
Ugll
0
Ugll
3
EPA 625
1.6
BENZIDINE
<1.6
Ugll
0
Ugn
3
EPA 625
1.6
BENZO(A)ANTHRACENE
<1.3
Ugll
0
Ugll
3
EPA 625
1.3
BENZO(A)PYRENE
<1.3
Ugll
0
Ugll
3
EPA 625
1.3
EPA Forth 3510-2A (Rev. 1-99). Replaces EPA fortes 7550-6 & 7550-22.
Page 12 of 22

n
FACILITY NAME AND PERMIT NUMBER:
PERMIT ACTION REQUESTED:
RIVER BASIN:
South Durham WRF, NCO047597
Renewal
Cape Fear
Outfall number: 001 (Complete once for each outfall discharging effluent to waters of the United States.)
MAXIMUM DAILY DISCHARGE
AVERAGE DAILY DISCHARGE
POLLUTANT
ANALYTICAL
MLIMDL
Number
Conc.
Units
Mass
Units
Conc.
Units
Mass
Units
of
METHOD
Samples
VOLATILE ORGANIC COMPOUNDS
ACROLEIN
0.0
Ugll
0
Ugll
3
EPA 624
4.0
ACRYLONITRILE
<3.5
Ugll
0
Ugll
3
EPA624
3.5
BENZENE
<0.15
Ugll
0
Ugll
3
EPA 624
0.15
BROMOFORM
<0.22
Ugll
0
Ugll
3
EPA 624
0.22
CARBON
TETRACHLORIDE
<0.17
Ugll
0
Ugn
3
EPA 624
0.17
CHLOROBENZENE
<0.17
Ugll
0
Ugll
3
EPA 624
0.17
CHLORODIBROMO-
<0.17
Ugll
0
Ugll
3
EPA 624
0.17
METHANE
CHLOROETHANE
<0.23
Ugll
0
Ugll
3
EPA 624
0.23
2-CHLOROETHYLVINYL
<7 1
Ugll
0
Ugll
3
EPA 624
1.10
ETHER
CHLOROFORM
<0.18
Ugll
0
Ugll
3
EPA 624
0.18
DICHLOROBROMO-
<0.17
Ugll
0
Ugll
3
EPA 624
0.17
METHANE
1,1-DICHLOROETHANE
<0.080
Ugll
0
Ugll
3
EPA 624
0.080
1,2-DICHLOROETHANE
<0.21
Ugll
0
Ugll
3
EPA 624
0.21
TRANS-I,2-0ICHLORO-
<0.12
Ugll
0
Ugll
3
EPA 624
0.12
ETHYLENE
1,1-DICHLORO-
<0.21
Ugll
0
Ugll
3
EPA 624
0.21
ETHYLENE
1,2-DICHLOROPROPANE
<0.10
Ugll
0
Ugn
3
EPA 624
0.10
1,3-DICHLORO-
<0.15
Ugll
0
Ugll
3
EPA 624
0.15
PROPYLENE
ETHYLBENZENE
<0.13
Ugll
0
Ugll
3
EPA 624
0.13
METHYLBROMIDE
METHYL CHLORIDE
METHYLENE CHLORIDE
<0.14
Ugll
0
Ugll
3
EPA 624
0.14
1,1,2,2-TETRA
<0.28
Ugll
0
Ugll
3
EPA 624
0.28
CHLOROETHANE
TETRACHLORO-
<0.17
Ugll
0
Ugn
3
EPA 624
0.17
ETHYLENE
TOLUENE
<0.14
Ugll
0
Ugll
3
EPA 624
0.14
EPA Form 3510-2A (Rev. 1-99). Replaces EPA forms 75506 & 7550-22.
Page 11 of 22

FACILITY NAME AND PERMIT NUMBER:
PERMIT ACTION REQUESTED:
RIVER BASIN:
South Durham WRF, NCO047597
Renewal
Cape Fear
Outfall number. 001 (Complete once for each outfall discharging effluent to waters of the United States.)
MAXIMUM DAILY DISCHARGE
AVERAGE DAILY DISCHARGE
POLLUTANT
ANALYTICAL
ML/MDL
Number
Conc.
Units
Mass
Units
Conc.
Units
Mass
Units
of
METHOD
Samples
3.4 BENZO-
<1.0
Ugll
0
Ugll
3
EPA 625
1.0
FLUORANTHENE
BENZO(GHI)PERYLENE
<2.4
Ugll
0
Ugll
3
EPA 625
2.4
BENZO(
0.3
Ugll
0
Ugll
3
EPA 625
1.3
FLUORANTHENE
BIS (2-CHLOROETHOXY)
11A
U911
0
Ugll
3
EPA 625
1.4
METHANE
BIS (2-CHLOROETHYL}
<1 2
Ugll
0
Ugll
3
EPA 625
1.2
ETHER
BIS (2-CHLOROISO-
<1,3
Ugll
0
Ugll
3
EPA 625
1.3
PROPYL)ETHER
BIS (2-ETHYLHEXYL)
11
Ugll
5
Ugll
3
EPA 625
1.7
PHTHALATE
4-BROMOPHENYL
41.0
Ugll
0
Ugll
3
EPA 625
1.0
PHENYL ETHER
BUTYL BENM
42.0
Ugll
0
Ugll
3
EPA 625
2,0
PHTHALATE
2-CHLORO-
<1.0
Ugll
0
Ugll
3
EPA 625
1.0
NAPHTHALENE
4-CHLORPHENYL
<1 6
Ugll
0
Ugll
3
EPA 625
1.6
PHENYL ETHER
CHRYSENE
<2.0
Ugll
0
Ugll
3
EPA 625
2.0
DI-N-BUTYL PHTHALATE
<1.5
Ugll
0
Ugll
3
EPA 625
1.5
DI-N-OCTYL PHTHALATE
<3.1
Ugll
0
Ugll
3
EPA 625
3.1
DIBENZO(A,H)
<2.3
Ugll
0
Ugli
3
EPA 625
2.3
ANTHRACENE
1,2-DICHLOROBENZENE
<1.1
Ugll
0
Ugll
3
EPA 625
1.1
1,3-DICHLOROSENZENE
<1.1
ugll
0
Ugll
3
EPA 625
1.1
1,4-DICHLOROSENZENE
<1.0
Ugll
0
Ugll
3
EPA 625
1.0
3,3-DICHLORO-
<3.3
Ugll
0
Ugll
3
EPA 625
3.3
BENZIDINE
DIETHYL PHTHALATE
<2.1
Ugll
0
Ugll
3
EPA 625
2.1
DIMETHYL PHTHALATE
<1.4
Ugll
0
Ugll
3
EPA 625
1A
2,4-DINFrROTOLUENE
42A
Ugn
0
Ug11
3
EPA 625
2A
2,6-DINITROTOLUENE
<1.5
Ugll
0
Ugll
3
EPA 625
1.5
1,2-DIPHENYL-
<1.5
Ugll
0
Ugll
3
EPA 625
1.5
HYDRAZINE
EPA Form 3510-2A (Rev. 1-99). Replaces EPA forms 7550E & 7550-22.
Page 13 of 22

/\
W
FACILITY NAME AND PERMIT NUMBER:
PERMIT ACTION REQUESTED:
RIVER BASIN:
South Durham WRF, NCO047597
Renewal
Cape Fear
Outfall number. 001 (Complete once for each outfall discharging effluent to waters of the United States.)
MAXIMUM DAILY DISCHARGE
AVERAGE DAILY DISCHARGE
POLLUTANT
ANALYTICAL
ML/MDL
Number
Conc.
Units
Mass
Units
Conc.
Units
Mass
Units
of
METHOD
Samples
FLUORANTHENE
42.1
Ug/I
0
Ug/I
3
EPA 625
2.1
FLUORENE
<1.7
Ug/I
0
Ug/I
3
EPA 625
1.7
HEXACHLOROBENZENE
<7.0
Ug/I
0
Ug/I
3
EPA 625
1.0
HEXACHLORO-
<7.2
Ugll
0
Ug/I
3
EPA 625
1.2
BUTADIENE
HEXACHLOROCYCLO-
41.3
Ug/I
0
Ug/I
3
EPA 625
1.3
PENTADIENE
HEXACHLOROETHANE
<11.11
Ug/I
0
Ugn
3
EPA 625
1.1
INDENO(1,2,3-CD)
<2,2
Ugll
0
Ug/I
3
EPA 625
2.2
PYRENE
ISOPHORONE
<1.3
Ug/I
0
Ug/I
3
EPA 625
1.3
NAPHTHALENE
<1.3
Ug/I
0
Ug/I
3
EPA 625
1.3
NITROBENZENE
<11.2
Ugll
0
Ug/I
3
EPA 625
1.2
N-NITROSODI-N-
<1.5
Lion
0
Ugn
3
EPA 625
1.5
PROPYLAMINE
N-NITROSODI-
<1.3
ug/I
0
Ugll
3
EPA 625
1.3
METHYLAMINE
N-NITROSODI-
<21
Ugn
0
Ugn
3
EPA 625
2.1
PHENYLAMINE
PHENANTHRENE
<1.4
Ug/I
0
U9/1
3
EPA 625
1.4
PYRENE
<2.1
Ug/I
0
Ug11
3
EPA 625
2.1
1,2,4-
<1.2
Ug/I
0
Ugll
3
EPA 625
1.2
TRICHLOROBENZENE
Use this space (or a separate sheet) to provide information on other base -neutral compounds requested by the permit writer
Use this space (or a separate sheet) to provide information on other pollutants (e.g., pesticides) requested by the permit writer
END OF PART D.
REFER TO THE APPLICATION OVERVIEW (PAGE 1) TO DETERMINE WHICH OTHER PARTS
OF FORM 2A YOU MUST COMPLETE
EPA Form 3510-2A (Rev. 1-99). Replaces EPA forms 7550-6 & 7550-22.
Page 14 of 22

/NVAk
r^
FACILITY NAME AND PERMIT NUMBER:
PERMIT ACTION REQUESTED:
RIVER BASIN:
South Durham WRF, NCO047597
Renewal
Cape Fear
SUPPLEMENTAL APPLICATION INFORMATION
PART E. TOXICITY TESTING DATA
POTWs meeting one or more of the following criteria must provide the results of whole effluent toxicity tests for acute or chronic toxicity for each of the
facility's discharge points: 1) POTWs with a design flow rate greater than or equal to 1.0 mgd; 2) POTWs with a pretreatment program (or those that are
required to have one under 40 CFR Part 403); or 3) POTWs required by the permitting authority to submit data for these parameters.
• At a minimum, these results must include quarterly testing for a 12-month period within the past 1 year using multiple species (minimum of two
species), or the results from four tests performed at least annually in the four and one-half years prior to the application, provided the results
show no appreciable toxicity, and testing for acute and/or chronic toxicity, depending on the range of receiving water dilution. Do not Include
information on combined sewer overflows in this section. All information reported must be based on data collected through analysis conducted
using 40 CFR Part 136 methods. In addition, this data must comply with QA/OC requirements of 40 CFR Part 136 and other appropriate OA/QC
requirements for standard methods for analyles not addressed by 40 CFR Part 136.
• In addition, submit the results of any other whole effluent toxicity tests from the past four and one-half years. If a whole effluent toxicity test
conducted during the past four and one-half years revealed toxicity, provide any information on the cause of the toxicity or any results of a
toxicity reduction evaluation, if one was conducted.
• If you have already submitted any of the information requested in Part E, you need not submit it again. Rather, provide the information
requested in question EA for previously submitted information. If EPA methods were not used, report the reasons for using alternate methods.
If test summaries are available that contain all of the information requested below, they may be submitted in place of Part E.
If no biomonitoring data is required, do not complete Part E. Refer to the Application Overview for directions on which other sections of the forth to
complete.
EA. Required Tests.
Indicate the number of whole effluent toxicity tests conducted in the past four and one-half years.
® chronic ❑ acute
E.2. Individual Test Data. Complete the following chart for each whole effluent toxicity test conducted in the last four and one-half Years. Allow one
column per test (where each species constitutes a test). Copy this page if more than three tests are being reported.
Test number. Test number: Test number:
a. Test information.
Test Species & test method number
Age at initiation of test
Outfall number
Dates sample collected
Date test started
Duration
b. Give toxicity test methods followed.
Manual titre
Edition number and year of publication
Page numbers)
c. Give the sample collection method(s) used. For multiple grab samples, indicate the number of grab samples used.
24-Hour composite
X
X
X
Grab
d. Indicate where the sample was taken in relation to disinfection. (Check all that apply for each.
Before disinfection
After disinfection
X
X
X
After dechlorination
EPA Form 351 G-2A (Rev. 1-99). Replaces EPA forms 7550-6 & 7550-22.
Page 15 of 22

100\
FACILITY NAME AND PERMIT NUMBER:
South Durham WRF, NCO047597
PERMIT ACTION REQUESTED:
Renewal
RIVER BASIN:
Cape Fear
Test number: Test number: Test number:
e. Describe the point in the treatment process at which the sample was collected.
Sample was collected:
Effluent
Effluent
Effluent
f. For each test, include whether the test was intended to assess chronic toxicity, acute toxicity, or both
Chronic toxicity
Acute toxicity
g. Provide the type of test performed.
Static
Static -renewal
Flow through
h. Source of dilution water. If laboratory water, specify type; if receiving water, specify source.
Laboratory water
Receiving water
I. Type of dilution water. If salt water, specify "natural" or type of artificial sea salts or brine used.
Fresh water
Salt water
j. Give the percentage effluent used for all concentrations in the test series.
k. Parameters measured during the test. (State whether parameter meets test method specifications)
pH
Salinity
Temperature
Ammonia
Dissolved oxygen
I. Test Results.
Acute:
Percent survival in 100%
effluent
%
%
o
�0
LC,
95% C.I.
%
%
%
Control percent survival
%
%
%
Other (describe)
EPA Form 3510-2A (Rev. 1-99). Replaces EPA forms 7550-6 & 7550-22.
Page 16 of 22

n
/\
00%
FACILITY NAME AND PERMIT NUMBER:
South Durham WRF, NCO047597
PERMIT ACTION REQUESTED:
Renewal
RIVER BASIN:
Cape Fear
Chronic:
NOEC
%
%
%
IC25
%
%
%
Control percent survival
%
%
%
Other (describe)
m. Quality Control/Quallly Assurance.
Is reference toxicant data available?
Was reference toxicant test within
acceptable bounds?
What date was reference toxicant test
run (MM/DD/YYYY)?
Other (describe)
E.3. Toxicity Reduction Evaluation. Is the treatment works involved in a Toxicity Reduction Evaluation?
❑ Yes ® No If yes, describe:
Ed. Summary of Submitted Blomonitoring Test Information. If you have submitted biomonitoring test information, or information regarding the
cause of toxicity, within the past four and one-half years, provide the dates the information was submitted to the permitting authority and a summary
of the results.
Date submitted: / / (MM/DD/YYYY)
Summary of results: (see instructions)
END OF PART E.
REFER TO THE APPLICATION OVERVIEW (PAGE 1) TO DETERMINE WHICH OTHER PARTS
OF FORM 2A YOU MUST COMPLETE.
EPA Forth 3510-2A (Rev. 1-99). Replaces EPA forms 7550-6 & 7550-22.
Page 17 or22

FACILITY NAME AND PERMIT NUMBER:
PERMIT ACTION REQUESTED:
RIVER BASIN:
South Durham WRF, NCO047597
Renewal
Cape Fear
SUPPLEMENTAL APPLICATION INFORMATION
PART F.INDUSTRIAL USER DISCHARGES AND RCRAICERCLA WASTES
All treatment works receiving discharges from significant industrial users or which receive RCRA,CERCLA, or other remedial wastes must
complete part F.
GENERAL INFORMATION:
F.I. Pretreatment program. Does the treatment works have, or is subject to, an approved pretreatment program?
ID Yes ❑ No
F.2. Number of Significant Industrial Users (SIUs) and Categorical Industrial Users (CIUs). Provide the number of each of the following types of
industrial users that discharge to the treatment works.
a. Number of non -categorical SIUs. 4
b. Number of ClUs. 1
SIGNIFICANT INDUSTRIAL USER INFORMATION:
Supply the following information for each SIU. If more than one SIU discharges to the treatment works, copy questions F.3 through F.8 and
provide the information requested for each SIU.
F.3. Significant Industrial User Information. Provide the name and address of each SIU discharging to the treatment works. Submit additional pages
as necessary.
Name: Alsco
Mailing Address: 1720 Lawson Street
Durham, NC 27703
FA. Industrial Processes. Describe all the industrial processes that affect or contribute to the SIU's discharge.
Commercial laundering facility.
F.5. Principal Product(s) and Raw Material(s). Describe all of the principal processes and raw materials that affect or contribute to the SIU's
discharge.
Principal product(s): Laundry —shoo towels mats uniforms etc
Raw matenal(s): Laundry cleaning Products
F.6. Flow Rate.
a. Process wastewater flow rate. Indicate the average daily volume of process wastewater discharge into the collection system in gallons per
day (gpd) and whether the discharge is continuous or intermittent.
40,479 gpd (XX continuous or inlernittenl)
b. Non -process wastewater flow rate. Indicate the average daily volume of non -process wastewater flow discharged into the collection system
in gallons per day (gpd) and whether the discharge is continuous or intermittent.
2,891 gpd ()(X continuous or intermittent)
F.7. Pretreatment Standards. Indicate whether the SIU is subject to the following:
a. Local limits ® Yes ❑ No
b. Categorical pretreatment standards ❑ Yes ® No
If subject to categorical pretreatment standards, which category and subcategory?
EPA Form 3510-2A (Rev. 1-99). Replaces EPA forms 7550-6 & 7550-22.
Page 18 of 22

/NN%
FACILITY NAME AND PERMIT NUMBER:
PERMIT ACTION REQUESTED:
RIVER BASIN:
South Durham WRF, NCO047597
Renewal
Cape Fear
F.S. Problems at the Treatment Works Attributed to Waste Discharge by the SIU. Has the SIU caused or contributed to any problems (e.g.,
upsets, interference) at the treatment works in the past three years?
❑ Yes ® No If yes, describe each episode.
RCRA HAZARDOUS WASTE RECEIVED BY TRUCK, RAIL, OR DEDICATED PIPELINE:
F.9. RCRA Waste. Does the treatment works receive or has it in the past three years received RCRA hazardous waste by truck, rail or dedicated pipe?
❑ Yes ® No (go to F.12)
F.10. Waste transport Method by which RCRA waste is received (check all that apply):
❑ Truck ❑ Rail ❑ Dedicated Pipe
F.11. Waste Description. Give EPA hazardous waste number and amount (volume or mass, specify units).
EPA Hazardous Waste Number Amount Units
CERCLA (SUPERFUND) WASTEWATER, RCRA REMEDIATION/CORRECTIVE ACTION
WASTEWATER, AND OTHER REMEDIAL ACTIVITY WASTEWATER:
FA 2. Remediation Waste. Does the treatment works currently (or has it been notified that it will) receive waste from remedial activities?
❑ Yes (complete F.13 through F.15.) ® No
F.13. Waste Origin. Describe the site and type of facility at which the CERCLA/RCRA/or other remedial waste originates (or is excepted to origniate in
the next five years).
F.14. Pollutants. List the hazardous constituents that are received (or are expected to be received). Include data on volume and concentration, if
known. (Attach additional sheets if necessary.)
F.15. Waste Treatment.
a. Is this waste treated (or will be treated) prior to entering the treatment works?
❑ Yes ❑ No
If yes, describe the treatment (provide information about the removal efficiency):
b. Is the discharge (or will the discharge be) continuous or intermittent?
❑ Continuous ❑ Intermittent If intermittent, describe Discharge schedule.
END OF PART F.
REFER TO THE APPLICATION OVERVIEW (PAGE 1) TO DETERMINE WHICH OTHER PARTS
OF FORM 2A YOU MUST COMPLETE
EPA Form 3510-2A (Rev. 1-99). Replaces EPA forms 7550-5 & 7550-22.
P3QO 19 of 22

/M*,
FACILITY NAME AND PERMIT NUMBER:
PERMIT ACTION REQUESTED:
RIVER BASIN:
South Durham WRF, NCO047597
Renewal
Cape Fear
SUPPLEMENTAL APPLICATION INFORMATION
PART F.INDUSTRIAL USER DISCHARGES AND RCRAICERCLA WASTES
All treatment works receiving discharges from significant industrial users or which receive RCRA,CERCLA, or other remedial wastes must
complete part F.
GENERAL INFORMATION:
F.I. Pretreatment program. Does the treatment works have, or is subject to, an approved pretreatment program?
® Yes ❑ No
F.2. Number of Significant Industrial Users (SIUs) and Categorical Industrial Users (CIUs). Provide the number of each of the following types of
industrial users that discharge to the treatment works.
a. Number of non -categorical SlUs. 4
b. Number of ClUs. 1
SIGNIFICANT INDUSTRIAL USER INFORMATION:
Supply the following information for each SIU. If more than one SIU discharges to the treatment works, copy questions F.3 through F.8 and
provide the Information requested for each SIU.
F.3. Significant Industrial User Information. Provide the name and address of each SIU discharging to the treatment works. Submit additional pages
as necessary.
Name: Angelica
Mailing Address: 4 Anson Street
Durham, NC 27703
FA. Industrial Processes. Describe all the industrial processes that affect or contribute to the SIU's discharge.
Commercial laundering facility: Primarily hospital bedding.
F.S. Principal Product(s) and Raw Material(s). Describe all of the principal processes and raw materials that affect or contribute to the SIU's
discharge.
Principal product(s): Laundry— hospital bedding: sheets, pillowcases. etc.
Raw malerial(s): Laundry cleaning Products
F.6. Flow Rate.
a. Process wastewater flow rate. Indicate the average daily volume of process wastewater discharge into the collection system in gallons per
day (gpd) and whether the discharge is continuous or intermittent.
14,152 gpd (XX continuous or intermittent)
b. Non -process wastewater flow rate. Indicate the average daily volume of non -process wastewater flow discharged into the collection system
in gallons per day (gpd) and whether the discharge is continuous or intermittent.
931 gpd (XX continuous or intermittent)
F.7. Pretreatment Standards. Indicate whether the SIU is subject to the following:
a. Local limits ® Yes ❑ No
b. Categorical pretreatment standards ❑ Yes ® No
If subject to categorical pretreatment standards, which category and subcategory?
EPA Form 3510-2A (Rev. 1-99). Replaces EPA forms 7550-6 & 7550-22.
Page 20 of 22

n
/lbk
FACILITY NAME AND PERMIT NUMBER:
PERMIT ACTION REQUESTED:
RIVER BASIN:
South Durham WRF, NCO047597
Renewal
Cape Fear
F.B. Problems at the Treatment Works Attributed to Waste Discharge by the SIU. Has the SIU caused or contributed to any problems (e.g.,
upsets, interference) at the treatment works in the past three years?
❑ Yes ® No If yes, describe each episode.
RCRA HAZARDOUS WASTE RECEIVED BY TRUCK, RAIL, OR DEDICATED PIPELINE:
F.9. RCRA Waste. Does the treatment works receive or has it in the past three years received RCRA hazardous waste by truck, rail or dedicated pipe?
❑ Yes ® No (go to F.12)
F.10. Waste transport Method by which RCRA waste is received (check all that apply):
❑ Truck ❑ Rail ❑ Dedicated Pipe
F.11. Waste Description. Give EPA hazardous waste number and amount (volume or mass, specify units).
EPA Hazardous Waste Number Amount Units
CERCLA (SUPERFUND) WASTEWATER, RCRA REMEDIATION/CORRECTIVE ACTION
WASTEWATER, AND OTHER REMEDIAL ACTIVITY WASTEWATER:
FA 2. Remediation Waste. Does the treatment works currently (or has it been notified that it will) receive waste from remedial activities?
❑ Yes (complete F.13 through F.15.) ® No
F.13. Waste Origin. Describe the site and type of facility at which the CERCLAIRCRAtor other remedial waste originates (or is excepted to origniate in
the next five years).
F.14. Pollutants. List the hazardous constituents that are received (or are expected to be received). Include data on volume and concentration, if
known. (Attach additional sheets if necessary.)
F.15. Waste Treatment
a. Is this waste treated (or will be treated) prior to entering the treatment works?
❑ Yes ❑ No
If yes, describe the treatment (provide information about the removal efficiency):
b. Is the discharge (or will the discharge be) continuous or intermittent?
❑ Continuous ❑ Intermittent If intermittent, descdbe discharge schedule.
END OF PART F.
REFER TO THE APPLICATION OVERVIEW (PAGE 1) TO DETERMINE WHICH OTHER PARTS
OF FORM 2A YOU MUST COMPLETE
EPA Form 3510-2A (Rev. 1-99). Replaces EPA forms 7550-6 & 7550-22.
Page 21 of 22

f=
-40wk
FACILITY NAME AND PERMIT NUMBER:
PERMIT ACTION REQUESTED:
RIVER BASIN:
South Durham WRF, NCO047597
Renewal
Cape Fear
SUPPLEMENTAL APPLICATION INFORMATION
PART F.INDUSTRIAL USER DISCHARGES AND RCRA/CERCLA WASTES
All treatment works receiving discharges from significant industrial users or which receive RCRA,CERCLA, or other remedial wastes must
complete part F.
GENERAL INFORMATION:
F.I. Pretreatment program. Does the treatment works have, or is subject to, an approved pretreatment program?
® Yes ❑ No
F.2. Number of Significant Industrial Users (SIUs) and Categorical Industrial Users (Clue). Provide the number of each of the following types of
industrial users that discharge to the treatment works.
C. Number of non -categorical SIUs. 4
d. Number of ClUs. 1
SIGNIFICANT INDUSTRIAL USER INFORMATION:
Supply the following Information for each SIU. If more than one SIU discharges to the treatment works, copy questions F.3 through F.6 and
provide the Information requested for each SIU.
F.3. Significant Industrial User Information. Provide the name and address of each SIU discharging to the treatment works. Submit additional pages
as necessary.
Name: Unifirst
Mailing Address: 1409 Person Street
Durham, NC 27703
FA. Industrial Processes. Describe all the industrial processes that affect or contribute to the SIU's discharge.
Commercial laundering facility.
F.S. Principal Product(s) and Raw Material(s). Describe all of the principal processes and raw materials that affect or contribute to the SIU's
discharge.
Principal product(s): Laundry — shoo towels mats uniforms etc
Raw materal(s): Laundry cleaning products
F.6. Flow Rate.
C. Process wastewater Flow rate. Indicate the average daily volume of process wastewater discharge into the collection system in gallons per
day (gpd) and whether the discharge is continuous or intermittent.
63,605 gpd (xxx continuous or intermittent)
d. Non -process wastewater Flow rate. Indicate the average daily volume of non -process wastewater flow discharged into the collection system
in gallons per day (gpd) and whether the discharge is continuous or intermittent.
2,006 gpd I= continuous or intermittent)
F.7. Pretreatment Standards. Indicate whether the SIU is subject to the following:
a. Local limits ® Yes ❑ No
b. Categorical pretreatment standards ❑ Yes ® No
If subject to categorical pretreatment standards, which category and subcategory?
EPA Forth 3510-2A (Rev. 1-99). Replaces EPA forms 7550-6 & 7550-22.
Page 22 of 22

/\
FACILITY NAME AND PERMIT NUMBER:
PERMIT ACTION REQUESTED:
RIVER BASIN:
South Durham WRF, NCO047597
Renewal
Cape Fear
F.8. Problems at the Treatment Works Attributed to Waste Discharge by the SIU. Has the SIU caused or contributed to any problems (e.g.,
upsets, interference) at the treatment works in the past three years?
❑ Yes ® No If yes, describe each episode.
RCRA HAZARDOUS WASTE RECEIVED BY TRUCK, RAIL, OR DEDICATED PIPELINE:
F.9. RCRA Waste. Does the treatment works receive or has it in the past three years received RCRA hazardous waste by truck, rail or dedicated pipe?
❑ Yes ® No (go to F.12)
F.10. Waste transport Method by which RCRA waste is received (check all that apply):
❑ Truck ❑ Rail ❑ Dedicated Pipe
FA 1. Waste Description. Give EPA hazardous waste number and amount (volume or mass, specify units).
EPA Hazardous Waste Number Amount Units
CERCLA (SUPERFUND) WASTEWATER, RCRA REMEDIATION/CORRECTIVE ACTION
WASTEWATER, AND OTHER REMEDIAL ACTIVITY WASTEWATER:
F.12. Remediation Waste. Does the treatment works currently (or has it been notified that it will) receive waste from remedial activities?
❑ Yes (complete F.13 through F.15.) ® No
F.13. Waste Origin. Describe the site and type of facility at which the CERCLA/RCRA/or other remedial waste originates (or is excepted to origniate in
the next five years).
F.14. Pollutants. List the hazardous constituents that are received (or are expected to be received). Include data on volume and concentration, if
known. (Attach additional sheets if necessary.)
F.15. Waste Treatment
C. Is this waste treated (or will be treated) prior to entering the treatment works?
❑ Yes ❑ No
If yes, describe the treatment (provide information about the removal efficiency):
d. Is the discharge (or will the discharge be) continuous or intermittent?
❑ Continuous ❑ Intermittent If intermittent, describe discharge schedule.
END OF PART F.
REFER TO THE APPLICATION OVERVIEW (PAGE 1) TO DETERMINE WHICH OTHER PARTS
OF FORM 2A YOU MUST COMPLETE
EPA Form 3510-2A (Rev. 1-99). Replaces EPA forms 7550-6 d 7550-22.
Page 23 of 22

AMA,
/MA,
FACILITY NAME AND PERMIT NUMBER:
PERMIT ACTION REQUESTED:
RIVER BASIN:
South Durham WRF, NCO047597
Renewal
Cape Fear
SUPPLEMENTAL APPLICATION INFORMATION
PART F.INDUSTRIAL USER DISCHARGES AND RCRAICERCLA WASTES
All treatment works receiving discharges from significant industrial users or which receive RCRA,CERCLA, or other remedial wastes must
complete part F.
GENERAL INFORMATION:
F.1. Pretreatment program. Does the treatment works have, or is subject to, an approved pretreatment program?
® Yes ❑ No
F.2. Number of Significant Industrial Users (SIUs) and Categorical Industrial Users (CIUs). Provide the number of each of the following types of
industrial users that discharge to the treatment works.
e. Number of non -categorical SlUs. 4
f. Number of ClUs. 1
SIGNIFICANT INDUSTRIAL USER INFORMATION:
Supply the following Information for each SIU. If more than one SIU discharges to the treatment works, copy questions F.3 through F.8 and
provide the information requested for each SIU.
F.3. Significant Industrial User Information. Provide the name and address of each SIU discharging to the treatment works. Submit additional pages
as necessary.
Name:. Technicoal
Mailing Address: 1669 Cooper Street
Durham, NC 27703
FA. Industrial Processes. Descdbe all the industrial processes that affect or contribute to the SIU's discharge.
Commercial laundering facility.
F.5. Principal Product(s) and Raw Material(s). Describe all of the principal processes and raw materials that affect or contribute to the SIU's
discharge.
Principal product(s): Powdercoating of metal parts
Raw malerial(s): Cleanerscoaters and sealants. caustic
F.6. Flow Rate.
e. Process wastewater flow rate. Indicate the average daily volume of process wastewater discharge into the collection system in gallons per
day (gpd) and whether the discharge is continuous or intermittent.
5,814 gpd (rope continuous or intermittent)
I. Non -process wastewater flow rate. Indicate the average daily volume of non -process wastewater flow discharged into the collection system
in gallons per day (gpd) and whether the discharge is continuous or intermittent.
1,870 gpd (xxx continuous or intermittent)
F.7. Pretreatment Standards. Indicate whether the SIU is subject to the following:
a. Local limits ® Yes ❑ No
b. Categorical pretreatment standards ® Yes ❑ No
If subject to categorical pretreatment standards, which category and subcategory?
433.17 - PSNS
EPA Form 3510-2A (Rev. 1-99). Replaces EPA fortes 7550-6 & 7550-22.
Page 24 of 22

i^
FACILITY NAME AND PERMIT NUMBER:
PERMIT ACTION REQUESTED:
RIVER BASIN:
South Durham WRF, NCO047597
Renewal
Cape Fear
F.B. Problems at the Treatment Works Attributed to Waste Discharge by the SIU. Has the SIU caused or contributed to any problems (e.g.,
upsets, interference) at the treatment works in the past three years?
❑ Yes E No If yes, describe each episode.
RCRA HAZARDOUS WASTE RECEIVED BY TRUCK, RAIL, OR DEDICATED PIPELINE:
F.9. RCRA Waste. Does the treatment works receive or has it in the past three years received RCRA hazardous waste by truck, rail or dedicated pipe?
❑ Yes E No (go to F.12)
F.10. Waste transport Method by which RCRA waste is received (check all that apply):
❑ Truck ❑ Rail ❑ Dedicated Pipe
F.11. Waste Description. Give EPA hazardous waste number and amount (volume or mass, specify units).
EPA Hazardous Waste Number Amount Units
CERCLA (SUPERFUND) WASTEWATER, RCRA REMEDIATION/CORRECTIVE ACTION
WASTEWATER, AND OTHER REMEDIAL ACTIVITY WASTEWATER:
F.12. Remedlation Waste. Does the treatment works currently (or has it been notified that it will) receive waste from remedial activities?
❑ Yes (complete F.13 through F.15.) E No
F.13. Waste Origin. Describe the site and type of facility at which the CERCLA/RCRA/or other remedial waste originates (or is excepted to origniate in
the next five years).
F.14. Pollutants. List the hazardous constituents that are received (or are expected to be received). Include data on volume and concentration, if
known. (Attach additional sheets if necessary.)
F.15. Waste Treatment
e. Is this waste treated (or will be treated) prior to entering the treatment works?
❑ Yes ❑ No
If yes, describe the treatment (provide information about the removal efficiency):
I. Is the discharge (or will the discharge be) continuous or intermittent?
❑ Continuous ❑ Intermittent If intermittent, describe discharge schedule.
END OF PART F.
REFER TO THE APPLICATION OVERVIEW (PAGE 1) TO DETERMINE WHICH OTHER PARTS
OF FORM 2A YOU MUST COMPLETE
EPA Forth 3510-2A (Rev. 1-99). Replaces EPA forms 7550E & 7550-22.
Page 25 of 22

r� SOUTH DURHAM WATER RECLAMATION FACILITY
NPDES Permit NCO047597
Plant Overview
Sludge Management Narrative
Back-up Generator Narrative
RECEIVEDIDENRIDWR
OCT 302015
Water Quality
Permitting Section

Section 2
Overview of Existing Facilities
This section of the Master Plan summarizes the existing treatment facilities at the
South Durham Water Reclamation Facility (SDWRF). Before improvements to
the facility can be recommended, a thorough analysis of the current plant
operation and the treatment capacity of each process must be determined and
understood.
2.1 Introduction
The SDWRF was originally constructed in 1984 as the Farrington Road
Wastewater Treatment Plant. The Farrington Road Plant was a 10 mgd facility
constructed to replace four small existing wastewater plants. Two of the existing
facilities, the Sandy Creek Plant and the Hope Valley Plant were temporary
package -type facilities. The other two, the New Hope Plant and the Third Fork
Plant, were old facilities and were significantly overloaded and performing poorly.
The Farrington Road plant was upgraded in the late 1980's. Solids handling and
dewatering facilities were expanded and biological phosphorus removal facilities
and tertiary filtration were added. No increase in treatment capacity was provided
in the upgrade. In 1994, the plant was expanded to a biological nutrient removal
facility with a rated capacity of 20 mgd. Ultraviolet disinfection, gravity belt
thickening of waste activated solids and odor control were also included in this
project. The upgraded facility, with its advanced level of treatment, was renamed
The South Durham Water Reclamation Facility.
A flow diagram of the existing facilities is provided in Figure 2-1.
SDWRF 2011 Master Plan 2-1 Section 2 — Overview of Existing
Facilities

N
N
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Figure 34
Existing SOWRF Prmss Flow Diagram
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2.2 Preliminary Facilities
Flow enters the SDWRF primarily by gravity at the preliminary facilities.
Preliminary treatment facilities at the SDWRF consist of mechanically cleaned
bar screens, influent pumps, and grit removal equipment.
Bar Screens
Influent wastewater passes through a splitter box where it is divided into two
streams. Each stream then passes through a mechanically cleaned Vulcan bar
screen:
Number of screens 2
Channel width, feet 6
Maximum channel depth, feet 16
Flow rate per screen, mgd
Maximum 30
Average 10
Opening between bars, inches '14
Each screen has a maximum capacity of 30 mgd. This provides firm screening
capacity at the maximum month flow of 24 mgd and capability to handle the peak
flow of 60 mgd.
Screenings are discharged to a dumpster for off -site disposal.
Influent Pumps
After screening, the influent wastewater flows into two adjoining wet wells. A 42-
inch sluice gate is provided between the wet wells so that they may operate
separately or as one. The influent pump station is equipped with four vertical
centrifugal pumps. Two pumps withdraw from each well. Each pump is equipped
with both a variable frequency drive (VFD) and a bypass starter. This allows the
pumps to run at maximum speed in the event of failure of the VFDs. This pump
and wet well arrangement provide great flexibility for operation and maintenance
of the pump station. Design and specification information for the influent pumps
follows:
SDWRF 2011 Master Plan 2-3 Section 2 — Overview of Existing
Facilities

.•.
Number of pumps 4
Manufacturer
Type
Maximum Capacity, mgd
Fairbanks Morse
Variable speed, non -clog,
centrifugal
23
The four influent pumps provide a firm capacity of 69 mgd. The influent pump
station has firm capacity to handle peak flows through the facility.
Grit Removal
Wastewater from the Influent Pump Station discharges through one 36-inch and
one 42-inch force main to the Grit Influent Splitter Box. Flow from the off -site
Stagecoach Road Pump Station combines with flow from the Influent Pump
Station at the Grit Influent Splitter Box, and the combined flow is distributed to the
grit removal facilities.
Four horizontal flow, velocity controlled grit removal units remove and collect grit
from the influent wastewater. The wastewater flow is split into two streams in the
Grit Influent Splitter Box. Each stream is split again and directed through one of
four grit removal channels. Gates in the channels provide flexibility to take any of
the channels out of service for maintenance. The following summarizes design
information for the grit collectors:
Number
Type
Manufacturer
Capacity, mgd
Method of grit removal
4
Horizontal flow, velocity control
E&I Corporation
15
Chain and bucket
SDWRF 2011 Master Plan 2-4 Section 2—Overview of Existing
Facilities
/O�
n

r�
At the design flow, the velocity of the wastewater entering the grit channels is
reduced to an average of one foot per second to allow the heavier grit and
inorganic particles to settle to the bottom of the channels. The settled grit is
collected with a chain and bucket system, is washed, conveyed to a dumpster
and disposed of off -site.
2.3 Primary Treatment Facilities
Primary treatment facilities at the SDWRF include primary settling basins,
primary solids pumping equipment and scum removal equipment.
Primary Settlinq Basins
Wastewater that has been screened and processed through the grit removal
facilities flows to the primary settling basins. The SDWRF has four rectangular
AO► primary settling basins. The influent structure provides capability to route the flow
to all four basins or just to Basins 1 and 2 or just to Basins 3 and 4. There is also
rMQ
capability to remove any of the basins from service while maintaining flow
through the other three. Primary Settling Basin design information follows:
Number 4
Dimensions
Width, feet 40
Length, feet 98
Average sidewater depth, feet 10.5
Surface area per basin, sf 3,920
Total surface area, sf 15,680
Overflow rate
Avg. flow (20 mgd), gpd/sf 1275
Max. mo. flow (24 mgd), gpd/sf 1530
Peak flow (60 mgd), gpd/sf 3825
SDWRF 2011 Master Plan 2-5 Section 2 — Overview of Existing
Facilities

Although these overflow rates are slightly higher than normal primary clarification
loading rates, they are reasonable to achieve removal of the primary solids at the
design flows. These rates are generally considered appropriate for biological
nutrient removal (BNR) plants where the higher loading rates allow more of the
influent carbon to pass to the downstream processes to enhance biological
nitrogen and phosphorus removal.
Primary Solids Pumping
Two pump stations remove primary solids from the primary settling basins.
Primary Solids Pump Station 1-2 removes solids from Basins 1 and 2. Primary
Solids Pump Station 3-4 removes solids from Basins 3 and 4. Each pump station
is equipped with two progressing cavity pumps with in -line solids grinders. The
pumps remove primary solids from the basins and pump them to the digesters.
Design information for the primary solids pumps follows:
Number
EI
Manufacturer Netzsch
Capacity, gpm 125
The pump stations provide a firm primary solids pumping capacity of 250 gpm.
At the maximum month facility flow of 24 mgd, primary solids flow is estimated to
be 172,360 gpd. This is based on an estimated 28,750 lb/day of solids at 2%
solids concentration. The primary solids pumps only need to run 11.5 hours per
day at 250 gpm to handle the maximum month solids production.
Primary solids pumping is adequate to handle solids production at the SDWRF
design flows.
Primary Scum Pumping
Scum is removed from each of the settling basins with scum skimmer pipes.
Each basin is equipped with two rotating skimmer pipes. When the pipes are
rotated, scum flows from the surface of the basin to the scum pump wet well. e*1
SDWRF 2011 Master Plan 2-6 Section 2 — Overview of Existing
Facilities

^►,
n
The scum pump station is equipped with in line grinders and constant speed
centrifugal screw pumps as follows:
Number
Manufacturer
Type
Capacity, gpm
K
Hayward Gordon, Ltd.
Screw -centrifugal
150
The primary scum pumps convey scum to the scum concentrator in the Scum
Concentrator Building. The scum concentrator has a working volume of 3,900
gallons and can handle flows up to 150 gpm. The scum concentrator removes
water from the scum and discharges the solids to a dumpster for off -site disposal.
The scum pump station has a firm capacity of 150 gpm. This is the maximum
flow to the concentrator, and is sufficient to handle scum flows from the four
primary settling basins.
There is no redundancy for the scum concentrator, however the equipment has
been reliable. Consideration will be given in the future to transferring primary
scum to the anaerobic digestion process rather than disposing of the material off -
site. This would also aid in gas production in the digesters.
2.4 Secondary Treatment Facilities
Secondary treatment at the SDWRF includes anaerobic tanks and aeration
basins, blowers, final clarifiers, RAS pump stations and alum feed facilities. The
system is designed to remove BOO, suspended solids, phosphorus, and nitrogen
to the levels required by the NPDES permit.
The activated sludge process is designed such that it can be operated in any of
four different modes. By varying the oxygen levels and detention times in the
anoxic and aeration basins, the facility can operate in the modified Bardenpho
SDWRF 2011 Master Plan 2-7 Section 2—Overview of Existing
Facilities

process mode, the three -stage Phoredox process mode, the OWASA process
mode or the Modified Biological Phosphorus Removal (MBPR) process mode.
The SDWRF typically operates in the modified Bardenpho mode (5 stage) for
biological removal of nitrogen and phosphorus.
Anaerobic Tanks and Aeration Basins
After primary treatment, the primary effluent flows to the Anaerobic Tanks. There
are two Anaerobic tanks which are 240' by 30' originally constructed as anoxic
tanks. These tanks operate with a side water depth of 15.25 feet. This provides a
detention time of two hours at the design flow of 20 mgd. Each basin is equipped
with eight submersible mixers to keep solids in suspension while minimizing the
introduction of oxygen. Return activated sludge can be returned to the influent of
the anaerobic tanks or to the middle of each tank.
There are eight aeration basins at the facility:
Aeration Basins 1-4
Dimensions of each basin
Length, feet
304
Width, feet
50
Depth, feet
15.25
Volume, mg
1.71
Total Volume, mg
6.84
Aeration Basins 5-8
Dimensions of each basin:
Length, feet
304
Width, feet
75
Depth, feet
15
Volume, mg
2.56
Total Volume, mg
10.24
Influent is split proportionately to the aeration basins to provide 20.5 hours of
detention time at the design flow of 20 mgd, and 17.1 hours of detention at the
maximum month flow of 24 mgd.
SDWRF 2011 Master Plan 2-8 Section 2 — Overview of Existing
Facilities
n
I'a

The aeration basins, influent channels and effluent channels are equipped with a
combination of fine and coarse bubble diffusers, jet mixer/aerators, mixing pumps
and mixed liquor recirculation pumps to provide varying combinations of aeration
and mixing. Each basin is provided with separate cells divided by baffle walls to
allow operation of selected cells in either aerobic or anoxic mode.
In the modified Bardenpho process both nitrogen and phosphorus are removed
in a single activated sludge treatment stage. At the SDWRF, return activated
sludge removed from the clarifiers is mixed with the influent wastewater in the
anaerobic tanks. The anaerobic tanks are the first stage of the BNR process.
The remaining four stages of the process are provided in the aeration basins.
Two separate anoxic stages are used to accomplish biological nitrogen removal
by denitrification. Mixed liquor recirculation is provided from the aeration zone to
the first anoxic zone to return nitrates for denitrification. Phosphorus uptake,
ammonia oxidation and BOD removal occur in the third, aerobic stage. Residual
nitrate from the aerobic zone is further denitrified in the second anoxic zone.
After passing through the second anoxic zone, flow enters the final or reaeration
stage. Reaeration provides oxidation of the remaining ammonia and raises
dissolved oxygen levels for subsequent treatment processes.
The design of the tanks and equipment for the activated sludge process at the
SDWRF provides the necessary detention times and oxygen levels to reach
NPDES permit limits on BOD, suspended solids, and phosphorus at the design
flow of 20 mgd and the maximum month flow of 24 mgd. Biological phosphorus
removal is also achieved.
Blowers
Process air for the aeration basins is provided by six blowers located in the
Blower Building, as follows:
Blowers 1-2 are motor -driven, rotary positive displacement blowers with a
rated capacity of 6700 cfm @ 880 rpm.
SDWRF 2011 Master Plan 2-9 Section 2 — Overview of Existing
Facilities

.'�N
Blowers 3-4 are engine -driven, rotary positive displacement blowers with a
rated capacity of 9950 cfm @1130 rpm.
Blowers 5-6 are motor -driven, single stage, centrifugal blowers with a
rated capacity 7900 cfm.
Total blower capacity is 49,100 cfm. Firm capacity is 39,150 cfm. Maximum day
air demand at 20 mgd is estimated at 37,800 cfm. The existing blower system is
adequate for the expected process air demands at design flows.
Final Clarifiers
Mixed liquor from the aeration basins flows to the final clarifiers. Settled solids
flow to the RAS pump stations and are returned to the aeration basins or are
wasted to the thickening facility and anaerobic digesters. Clarified effluent flows
to the filters for further treatment.
There are six final clarifiers at the SDWRF. Clarifiers 1-4 are smaller diameter
rim -feed type clarifiers. Clarifiers 5-6 are larger center -feed type. The original
design planned to split the flow proportionately to the six clarifiers. However,
several problems with the smaller clarifiers have prompted changes in the plant
operation. Historically, perimeter feed clarifiers do not perform as well as center
feed. In addition, Clarifiers 1-4 at the SDWRF were constructed with thin slab
foundations. Water pressure under the slabs has caused the slabs to heave and
the center columns and rotating mechanisms in the clarifiers have shifted. For
these reasons, all average daily flows are routed to Clarifiers 5 and 6. During
high flow conditions, a portion of the flow may be sent to Clarifiers 1-4. These
clarifiers are used for the duration of the high flow and are then removed from
service, and cleaned. Eventually, as average flow to the facility increases, new
secondary clarifiers will need to be constructed. The original clarifier design
information is summarized below:
SDWRF 2011 Master Plan 2-10 Section 2—Overview of Existing
Facilities

Clarifiers 1-4
Number
4
Type
Peripheral feed
Manufacturer
Envirex
Diameter, ft
80
Sidewater depth, ft
16
Surface area, each, sf
5,030
Total surface area, sf
20,120
Clarifiers 5-6
Number
2
Type
Center feed
Manufacturer
Envirex
Diameter, ft
120
Sidewater depth, ft
15.3
Surface area, each, sf
11,310
Total surface area, sf
22,620
Overflow rates at the design flows are summarized
below:
Avg flow (20 mgd), gpd/sf
470
Max mo flow (24 mgd), gpd/sf
580
Peak flow (60 mgd), gpd/sf
1,400
These overflow rates are well within acceptable limits for secondary clarifiers,
and are adequate to remove solids at the design flows.
RAS Pump Stations
Two RAS pump stations return activated sludge from the final clarifiers to the
anoxic tanks. RAS Pump Station No. 1 serves Final Clarifiers 1-4. RAS Pump
Station No. 2 serves Final Clarifiers 5-6. Both stations are equipped with variable
speed, vertical mixed flow pumps, as follows:
SDWRF 2011 Master Plan
2-11 Section 2 — Overview of Existing
Facilities

RAS Pump Station No. 1
Number 2
Manufacturer Worthington
Maximum Capacity, gpm 2,250
Number 2
Manufacturer Worthington
Maximum Capacity, gpm 2,900
The pump station has two adjoining wet wells with two pumps drawing from each
well. The wet wells are connected with a sluice gate so the wells may be
operated separately or as one. RAS Pump Station No. 1 has a firm capacity of
7,400 gpm.
RAS Pump Station No. 2
Number 3
Manufacturer Fairbanks Morse
Capacity, gpm 5,000
All three pumps draw from the same wet well. RAS Pump Station No. 2 has a
firm capacity of 10,000 gpm.
Together, the two RAS pump stations have a firm capacity of 17,400 gpm or 25
mgd. This provides firm pumping capacity to handle the return solids at the
maximum month flow to the SDWRF.
2.5 Tertiary Treatment Facilities
Tertiary treatment at the SDWRF includes rapid mix chambers, flocculation
basins, and effluent filters.
SDWRF 2011 Master Plan 2-12 Section 2—Overview of Existing
Facilities
r'1
n

Rapid Mix Chambers
Clarifier effluent piping conveys flow to the rapid mix chamber influent distribution
box which distributes flow to two rapid mix chambers before entering the
flocculation basins. Each chamber is equipped with one variable speed rapid
mixer to vigorously mix the wastewater with polymer.
The two 11,000 gallon rapid mix chambers provide 1.6 minutes of detention time
at the plant design flow of 20 mgd. At the maximum month flow of 24 mgd,
detention time is 1.3 minutes.
The two rapid mix chambers together are adequate to handle the plant design
flow.
Flocculation Basins
The SDWRF is equipped with four flocculation basins. Wastewater flows from
the rapid mix chambers to the Flocculation Basin Influent Channel. The channel
is equipped with sluice gates which can be used to shut off flow to each basin.
Each basin has an influent target baffle wall to prevent short-circuiting, four
variable speed flocculators, three interior baffle walls, and two effluent sluice
gates. The flocculators gently agitate the wastewater to maximize floc formation
and to prevent the floc from settling.
Each basin is designed to provide 24.5 minutes of detention time at an average
flow of 5 mgd. The detention time at the maximum month flow of 24 mgd, 6 mgd
to each basin, is 20.4 minutes.
The flocculation basins are adequate to handle the SDWRF design flows.
Effluent Filters
From the flocculation basins, the wastewater flows through the Flocculation
Effluent Junction Box and through two 48-inch pipes to the Filter Influent
SDWRF 2011 Master Plan 2-13 Section 2—Overview of Existing
Facilities

n
Distribution Channel. The channel is equipped with influent weirs, influent slide
gates, and bypass sluice gates; one for each filter. The filters are designed to
provide operational flexibility. Any of the filters may be removed from service by
lowering the influent slide gates to the filter. The bypass sluice gates can be
partially opened to allow some flow to bypass the filters if necessary during high
flow events if one or more filters are out of service. Filter design information
follows:
Number 4
Dimensions, each
Width, ft 15
Length, ft 111.7
Surface area, sf 1,675
Total surface area, sf 6,700
Hydraulic loading rate, gpm/sf
Avg flow (20 mgd) 2.1
Max mo flow (24 mgd) 2.5
Peak flow 6.2
These overflow rates are adequate to provide solids removal at the design flows.
2.6 Ultraviolet Disinfection System
Filtered effluent is conveyed to the Ultraviolet (UV) Disinfection facility through
two 48-inch pipelines. The UV Disinfection facility is equipped with six channels,
each containing a bank of UV lamps which are used to disinfect the wastewater.
Each channel is designed to handle flows ranging from 4.5 mgd to 9 mgd. A
control system consisting of influent butterfly valves, self-adjusting level control
gates, a programmable logic controller, and a system control center both
monitors and regulates the number of channels in use at any time. The system
also controls the flow to each channel. Individual channels can be isolated and
removed from service for cleaning or maintenance.
SDWRF 2011 Master Plan 2-14 Section 2—Overview of Existing
Facilities

The ultraviolet disinfection system is adequate to treat the average plant flow of
20 mgd, the maximum month plant flow of 24 mgd, and peak flows up to 54 mgd.
At the anticipated peak flow of 60 mgd, disinfection may be inadequate.
2.7 Solids Handling
All solids at the SDWRF are anaerobically digested, dewatered, and land
applied. Primary solids, as discussed previously, are pumped directly to the
anaerobic digesters. Waste activated solids are thickened and then pumped to
the digesters. Digested solids are dewatered on belt filter presses or sand drying
beds prior to land application.
Solids Thickening
Atft� Activated sludge thickening at the SDWRF is accomplished utilizing a gravity
thickener tank and gravity belt thickeners. The thickening system includes the
AWN
gravity thickener tank, gravity belt thickener feed pumps, thickened waste
activated sludge pumps, a polymer prep and feed system, gravity belt thickeners,
and all appurtenant equipment.
Gravity belt thickener design information:
Number
2
Manufacturer Klein America
Belt width, meters 2
Design criteria, each
Solids loading rate, Ib/hr 2,000
Hydraulic loading rate, gpm 500
SDWRF 2011 Master Plan 2-15 Section 2 — Overview of Existing
Facilities

At the maximum month flow of 24 mgd, the SDWRF wastes an estimated 28,300
lb/day of activated solids. Depending on the feed solids concentration, one
gravity belt thickener will operate between 14 and 19 hours a day to thicken
these solids. The facility has capacity to thicken the maximum month solids
production with one gravity belt out of service.
Three horizontal non -clog centrifugal pumps are provided to pump waste
activated solids to the gravity belt thickeners. One of the pumps is a standby for
the other two pumps. Variable flow is pumped to the thickeners by modulating a
motor -operated valve. Each pump can deliver 200-600 gpm to one of the
thickeners.
Two progressing cavity thickened waste activated sludge (TWAS) pumps are
provided to convey thickened solids to the anaerobic digesters. Each pump is
equipped with a variable frequency drive and is designed to pump 30-150 gpm.
One pump is located under a hopper at the discharge of each gravity belt
thickener. There is no redundancy in the TWAS pump design. If a TWAS pump is /'N
out of service, that gravity belt thickener cannot be used.
There is sufficient capacity and redundancy in the thickening facility at the
SDWRF to handle the anticipated maximum month solids production.
Anaerobic Digestion
Four anaerobic digesters provide stabilization of primary and secondary solids at
I07116* 11FA S
Two 70' diameter digesters were constructed in the 1980's. The digestion
facilities were upgraded in 1995, and two 85' diameter digesters were added.
The current facilities include:
SDWRF 2011 Master Plan 2-16 Section 2 — Overview of Existing
Facilities

r►,
Digesters 1-2
Number 2
Diameter, ft 70
Sidewater depth, ft.
22.4
Volume, each, cf
97,840
Total volume, cf
195,680
Digesters 3-4
Number 2
Diameter, ft 85
Sidewater depth, ft 28
Volume, each, cf 158,900
Total Volume, cf 317,800
The four anaerobic digesters provide a total volume of 513,500 cf or 3.84 million
gallons. The digesters are equipped with Infilco Degremont Cannon Mixing
Systems.
Solids production at the SDWRF is estimated as follows:
Annual Average
Waste activated solids, lb/day 21,650
Waste activated solids @ 6%, gpd 43,265
Primary solids, lb/day 22,150
Primary solids @ 4%, gpd 66,380
Maximum Month
Waste activated solids, lb/day 28,300
Waste activated solids @ 6%, gpd 56,555
Primary solids, lb/day 28,740
Primary solids @ 4%, gpd 86,150
The total flow to the digesters at average loading rates is an estimated 109,645
gpd. At this rate, the digesters provide 35 days of detention. At maximum month
loadings, the estimated total flow to the digesters is 142,705 gpd. This results in
SDWRF 2011 Master Plan 2-17 Section 2—Overview of Existing
Facilities

a detention time of 27 days. With one of the large digesters out of service, a
detention time of 18.6 days is still met at maximum month loadings. These
detention rates are sufficient to achieve digestion at temperatures of 95 degrees
Fahrenheit and above.
Solids Dewaterina
The SDWRF is equipped with belt filter presses for dewatering digested solids.
The facility also has 36 sand drying beds that can be used in addition to the belt
filter presses or as a back-up to the belt filter presses. A one acre stockpile area
is available for storing dewatered solids.
Belt Filter Press design information:
Number
Manufacturer
Belt Width, meters
Design criteria, each
Solids loading rate, Ib/hr
Hydraulic loading rate, gpm
3
2-Ashbrook, 1-Klein American
2
1,600
60-140
In order to dewater the maximum month digested solids production of 41,700
lb/day, the three belt filter presses would run 8.7 hours a day. Even with one
press out of service, the facility has capacity to dewater the maximum month
solids loading.
Four variable speed progressing cavity pumps feed the belt filter presses. Each
belt filter press has a designated feed pump with a design capacity of 200 gpm.
The fourth pump serves as a back-up to the other three.
The belt filter presses, in conjunction with the sand drying beds, provide a flexible
and reliable system for solids dewatering. The facilities are adequate to handle
maximum month solids production.
SDWRF 2011 Master Plan 2-18 Section 2 — Overview of Existing
Facilities
a
ems

2.8 Odor Control Facilities
Odor control facilities are provided at the SDWRF to remove gaseous hydrogen
sulfide. Hydrogen sulfide is a noxious, malodorous gas commonly emanating
from domestic wastewater treatment facilities. The SDWRF is equipped with
three countercurrent packed tower wet scrubbers. Foul air is drawn through
fiberglass ductwork to the scrubbers where a circulating caustic solution absorbs
the hydrogen sulfide. The airflow, is then discharged to the atmosphere. The
caustic solution is oxidized using sodium hypochlorite solution and then wasted
into the plant drain system.
The odor scrubber facilities at the SDWRF are summarized in Table 2-1:
Table 2-1
Odor Scrubbing Facilities
Process Units Served
Equipment
Belt Filter Press Building
One 11diameter vertical
packed tower scrubber
Blend Tanks
Odor Scrubber No. 1
One 28,250 cfm scrubber fan
Two 570 gpm scrubber
recirculation pum s
Preliminary Treatment
One 8' diameter vertical
Facilities
packed tower scrubber
Odor Scrubber No. 2
Primary Settling Tanks and
One 14,250 cfm scrubber fan
Effluent Channel
Two 300 gpm scrubber
PST Scum Pit
recirculation pumps
Influent Pump Station
One 11' diameter vertical
packed tower scrubber
Splitter Box and Wetwell
Odor Scrubber No. 3
One 3,000 cfm scrubber fan
Two 58 gpm scrubber
recirculation pumps
SDWRF 2011 Master Plan 2-19 Section 2 — Overview of Existing
Facilities

In addition to the equipment summarized above, caustic storage tanks,
recirculation pumps and transfer pumps are provided at the towers. Caustic
metering pumps are also provided at the towers, at the Influent Pump Station,
and at the Primary Settling Basins.
The odor control facilities at the SDWRF are adequate to keep hydrogen sulfide
emissions under 10 ppm, the maximum permissible 8-hour concentration
established by OSHA.
2.9 Instrumentation and Controls
The South Durham WRF was originally furnished with a manufactured
Distributed Control System, or DCS, as part of the major plant upgrade and
expansion in the mid-1990's. The DCS fully automated the facility, which placed
the City in the forefront of wastewater treatment plant automation at the time. By
the late 2000's, however, the DCS was obsolete and the manufacturer had gone
out of business, and thus the equipment and software were becoming difficult to
service and support. The City contracted with a local system integrator to
replace the DCS with a modern, non-proprietary control system based on
distributed PLCs (Programmable Logic Controllers) and PC -based operator
interface workstations. In general, new hardware was placed in the same
locations as the old DCS hardware. The new system, which is described below,
did not duplicate all of the functionality originally included with the DCS.
As noted above, the SDWRF has an extensive process monitoring and control
system that is called the SCADA system. The term "SCADA" stands for
"Supervisory Control and Data Acquisition." The SCADA System is comprised of
three basic components:
SDWRF 2011 Master Plan 2-20 Section 2 — Overview of Existing
Facilities

• Process Controllers
• PC -based Operator Workstations
• Ethernet Local Area Network (LAN)
The process controllers in the NDWRF SCADA system are based on Allen-
Bradley ControlLogix Programmable Automation Controllers, or PACs. PACs
may be considered as the technological successors to Programmable Logic
Controllers, or PLCs. They are faster, have much greater memory capacity, and
have more sophisticated programming capability than PLCs. The SCADA
system's PACs are distributed throughout the plant at locations based on the
process and near equipment to minimize wiring distances. Inputs and outputs
(1/0) to the controllers are routed to Allen-Bradley Point 1/0, which are then
networked to the local controller. The controllers are designed to operate
independently and will still be able to run the facility if the operator workstations
OOMIN are offline. Most functions would also still be available in the event that the
communication network is down.
The PC -based operator workstations use Allen -Bradley's RSView 32 Human -
Machine Interface (HMI) software to allow the operators to monitor and control
the facility. They provide graphic depictions of the plant and its equipment.
Operators can access the various displays, see the current status of equipment,
see the current operating parameters (flows, pressures, analytical values, etc.),
and effect control of the facility either in a remote manual mode or by engaging
and adjusting the automatic control strategies. The displays are hierarchical in
nature, with an overview that allows the operator to 'vector' to additional displays
by clicking on specific symbols and buttons with the mouse. Additional displays
to allow modification of automatic control strategies and setpoints, view alarms
and events, and view trends of data are also accessible.
SDWRF 2011 Master Plan 2-21 Section 2 — Overview of Existing
Facilities

The Ethernet communication network allows the various components of the
SCADA system to share data and pass commands. Operators may access any
plant monitoring and control functions from anywhere on the SCADA system
through this network. The network is non-proprietary, uses commercial off -the -
shelf hardware such as Hirschmann managed Ethernet switches, and is based
on fiber optic cable for complete immunity to electromagnetic noise and
interference. The fiber system is immune to damage from surges and spikes
caused by lightning as long as there is not a direct strike on equipment. The
SDWRF SCADA system is also connected to servers at the Division of Water
Resources Administration and Maintenance Facility on Mist Lake Drive. These
computers gather data from the SDWRF SCADA system for use by the Hach
WIMS data management software, which manages and prints operational and
laboratory data.
The control system performs three basic functions for the facility: r'N
1. Real-time process control
2. Information management
3. Overall process and facility management
Real-time process control is the minute -to -minute control of the facility's
processes and equipment, such as pumps, valves, aeration blowers, and effluent
filters. The SCADA system is designed to allow the plant to run automatically
under most conditions. Operators will therefore be freer to monitor the plant and
its processes, but will still have the ability to take over from the control system
when necessary.
e*1
SDWRF 2011 Master Plan 2-22 Section 2 — Overview of Existing
Facilities

The SCADA system is also a valuable tool for gathering and managing
information about the plant and its processes. It gathers a great deal of
information about the plant, such as status of equipment (run or fail), pressures,
levels, flows and other values. This information is stored by the control system
computers for use in reports, trends and process displays. Information is stored
in the short term on the computers' hard disk drives themselves and in the long
term (archived) on optical media. Trends of this data can be used for overall
planning and facility management.
2.10 Conclusion
The South Durham Water Reclamation Facility has firm capacity to treat the
average design flow of 20 mgd and associated maximum month loadings. The
influent pumps have firm capacity to convey the peak flow of 60 mgd through the
plant.
The preliminary facilities, although adequate in capacity, will need to be improved
in the future. Plant staff has indicated that distribution through the grit removal
facilities no longer functions as designed and heavy loads of grit enter the water
reclamation facility during peak flows causing equipment wear and other
problems downstream. Also, to increase gas production in the digesters and to
simplify operation, scum may be routed to the anaerobic digesters for treatment
in the future.
Primary and secondary treatment facilities are generally adequate to treat design
flows. However, improvements may be needed in these processes or in related
areas to allow consistent compliance with the Jordan Lake Rules for nutrients
and other regulatory requirements. The clarifier capacity of the existing failed
clarifiers will need to be addressed through major upgrades or clarifier
replacement as flow to the plant increases.
SDWRF 2011 Master Plan 2-23 Section 2 — Overview of Existing
Facilities

s
The tertiary filters are designed for solids removal at the average and maximum
month design flows. In peak wet weather flows, or if filters are out of service, flow
can be routed around the filters.
The ultraviolet disinfection facilities following the filters are designed to handle
flows up to 54 mgd. This provides adequate disinfection in all but the highest
flows anticipated at the plant.
Solids handling facilities at the plant have adequate capacity to treat all
anticipated flows through the facility. The design of the thickening, digestion and
dewatering facilities provide flexibility in both treatment and storage.
In summary, although there are issues that need to be addressed with several of
the unit processes at the plant, the South Durham Water Reclamation Facility is
constructed to treat the anticipated flows and meet the limits in place at the time
of design. Several of the processes may need to be upgraded to meet upcoming
regulatory limits.
n
SDWRF 2011 Master Plan 2-24 Section 2—Overview of Existing
Facilities

1.2 ANITA Mox MBBR Process Overview (Side Stream Treatment)
The ANITA Mox process is a type of moving bed biofilm reactor (MBBR). The MBBR process is
a continuous, flow -through, non -clogging biofilm reactor containing "carrier elements" or
media with a large surface area in a relatively small volume. The media does not normally
require backwashing or cleaning.
The biomass that treats water in the reactor is attached to the surfaces of the media forming
a biofilm. The media is designed to provide a large protected surface for the biofilm and
optimal conditions for biological activity when mixed in the reactor. Media is made from
polyethylene, which is slightly less dense than water.
The function of the ANITA Mox process is to remove ammonium from the filtrate stream
produced at the South Durham plant. This is accomplished by means of the deammonification
process. This biological process consists of an aerobic nitritation reaction and an anoxic
ammonia oxidation (anammox) reaction, as shown in Figure 1.
The two steps of deammonification take place simultaneously in different layers of the biofilm.
Nitritation occurs in the outer layer of the biofilm. Ideally, 55% of the influent ammonia is
oxidized to nitrite (NO2-). Anammox activity occurs in the inner layer. In this step, the nitrite
produced and the remaining ammonia are utilized by the anammox bacteria and converted to
nitrogen gas (N2) and a small amount of nitrate (NO3-).
The mixing of the media within MBBR reactors is usually provided by AnoxKaldnes' medium
bubble aeration system. The reactors also include mechanical mixers for supplemental
mixing during periods without aeration.
The ANITA Mox MBBR system for the South Durham WRF consists of two parallel trains, each
with one reactor. Upstream of the ANITA Mox reactors, is an equalization basin to store
filtrate, which is produced intermittently.
/4°

� Supplemental Carbon Feed
A supplemental carbon feed facility will go online in the first quarter of 2016. Glycerin is the
carbon source that will be used. The addition of a carbon food supply in the anoxic zone, after
the aeration zone, will improve the nitrogen removal capability of the treatment process. This
additional food will allow denitritication to go beyond what it currently can because of a
shortage of food for the biomass.
There are nine feed pumps that deliver the carbon to dedicated feed points. The eight aeration
basins have the option of feeding carbon into cell 5 (preferred) or into cell 6. The injection
points are on the line that sends flow into the cells for mixing. The other carbon feed point is
on the return activated sludge (RAS) line.

Table 2-2
Unit Treatment Capacities
CapacityUnit • Total
NumberTreatment Peak Hydraulic
Subsystem .. •
CapacityTreatment Hydraulic Out of Service
(MGD)
Li uid Train
Bar Screens
2
30.0
30.0
30.0
60.0
Influent Pump
4
23.0
23.0
69.0
96.0
Station
Grit Collectors
4
15.0
15.0
45.0
60.0
Primary Settling
4
6.7
15.0
20.0
60.0
Tanks
Anaerobic
2
10.0
30.0
10.0
60.0
Tanks
Aeration Tanks
Trains 1 - 4
4
2.4
6.0
20.0'
60.0
Trains 5-8
4
3.5
9.0
Secondary
Clarifiers -
Clarifiers 1 - 4
4
3.0
8.0
18.8
51.2
Clarifiers 5 - 6
2
6.8
1 14.0
Effluent Filters
4
6.3
15.0
20.0
59.6
UV Disinfection
6
9.0
9.0
45.0
54.0
' Temperature dependent
Subsystem
and based
NumberUnit
on current (2012Lperrrdt limits.
..
Solids
Handling
Gravity WAS
1
29,500
29,500
Thickener
Solids
2
38,400
76,800
Thickening
Anaerobic
Digestion
Digesters 1 - 2
2
20,350
40,700
Digesters 3 - 4
2
33,000
66,000
Solids
3
38,400
115,200
Dewaterin
SDWRF 2011 Master Plan 2-25 Section 2-Overview of Existing
Facilities

100.1\ SOUTH DURHAM WATER RECLAMATION FACILITY
SLUDGE MANAGEMENT PLAN
NPDES Permit NCO047597
— NARRATIVE DESCRIPTION
This narrative description of the sludge management plan for the South Durham Water
Reclamation Facility is submitted as a required component of the permit renewal
package.
The facility has four (4) rectangular primary clarifiers with a chain and flight collection
system. All primary sludge is pumped directly to the anaerobic digesters.
Waste activated sludge from the biological process is sent to a gravity thickener. Settled
solids are then pumped to gravity belt thickeners for dewatering. The thickened waste
activated sludge is then pumped to the anaerobic digesters.
The facility has four (4) anaerobic digesters with a total capacity of 3.84 million gallons.
They are operated in the mesophilic range in order to meet the EPA 503 criteria for Class
B Biosolids. Digested sludge is dewatered by belt filter presses or, on occasion, sand
drying beds. The facility has a 47,000 ft2 covered sludge storage pad. The drainage from
the pad is controlled and returned to the treatment facility.
The City of Durham contracts with a private company to operate a land application
program. The City of Durham holds permit WQ000304 for land application of
Biosolids. The City of Durham has land permitted in Durham and surrounding counties.
Our Contractor (currently Synagro, Inc.) removes biosolids from the storage pad,
transports it to the fields and applies it at agronomic rates. Under terms of the contract,
they adhere to all terms of the land application permit, including such items as
maintaining buffers, adjusting soil pH and conducting required analyses.
/°'R1

r0� SOUTH DURHAM WATER RECLAMATION FACILITY
NPDES Permit NCOO47597
BACK-UP GENERATORS
The South Durham WRF has four (4) back-up generators.
• A 5001(w natural gas generator is located in the engine/blower room of the Control
Building. This generator supplies power to the Control building, anaerobic digesters and
the preliminary and primary treatment facilities.
• A 5001(w natural gas and a 7501(w diesel fuel generator at the Influent Pump Station.
These generators supply power to the influent pumps, barscreens, filters and the UV
system.
• A 15001(w diesel fuel generator at the Electric Control Building. This generator supplies
power to the anaerobic tanks, aeration influent channel mixers, aeration basin mix and
recycle pumps, final clarifiers and return pumps.

(0k) SOUTH DURHAM WATER RECLAMATION FACILITY
NPDES Permit NC0047597
Plant Processes
Topography Maps
Aerial Photos
n

SOUTH DURHAM WATER RECLAMATION FACILITY
PLANT PROCESSES
NPDES Permit NCO047597
The following page has a diagram showing the average daily flow rates to the treatment
processes at the South Durham WRF.
The South Durham WRF is currently permitted for 20 MGD. The average annual flow rate for
the past several years has been approximately 9.10 MGD.
The following processes are not being fully utilized due to the low average daily flow rate.
• Three of four grit collectors are in service
• Two of four primary settling tanks are in service
• Four of eight aeration basins are in service
• Two of six final clarifiers are in service
t%ft1 All of the above units that are not in service are in operating condition and are available if
needed. Several of the above listed units may be put into service during high flow events.
Flow enters the plant at the Influent Pump Station where it passes through two barscreens. It is
pumped up to the four grit collectors. It then goes to the primary tanks, where scum and
sludge are separated from the wastewater. Scum and grit are collected and taken to the
landfill. Primary sludge is sent to the anaerobic digesters for treatment. After leaving the
Primaries, flow goes to the anaerobic tanks where the biological phosphorus removal process is
initiated. Flow then goes to the aeration basins where a modified 5-stage Bardenpho
treatment system is used to treat the wastewater and achieve phosphorus uptake and nitrogen
removal. Flow then goes to the final clarifiers, filters, then to UV for disinfection.
Wasted solids from the treatment process are thickened with gravity belt thickeners and then
pumped into the anaerobic digesters. Digested sludge is dewatered with belt presses. The
pressed biosolids are taken to a sludge storage pad and then land applied. The filtrate from
dewatering is sent to a side stream process which may remove up to 90% of the ammonia load.
Methane gas produced in the anaerobic digesters is utilized to run two engine driven blowers.
A supplemental carbon (glycerin) feed facility will come online in the first quarter of 2016. The
addition of a carbon food supply in the aeration basins will improve the plant's ability to
remove nitrogen.

,0r /O .M GD
PLANT
-INFLUENT
BAR
SCREENS
(2)
INFLUENT
PUMP
STATION
SCUM
CONCENTRATOR
LEGEND
NORMAL OPERATION
ALTERNATE OPERATION
D8
DIGESTED BIOSOUDS
F
FILTRATE
FB
FILTER BACKWASH
FBR
FILTER BACKWASH RETURN
FE
FILTER EFFLUENT
ML
MIXED LIQUOR
MLR
MIXED LIQUOR RECIRCULATION
Y
a
PE
PRIMARY EFFLUENT
PS
PRIMARY SOLIDS
RAS
RETURN ACTIVATED SLUDGE
SC
scum
SU
DIGESTER SUPERNATANT
TS
THICKENED SOLIDS
TSU
THICKENER SUPERNATANT
UR
UNDERDRAIN RETURN
u
WAS
WASTE ACTIVATED SLUDGE
PUMPS
a
HAZENAND SAWYER
Environmental Engineers & Scientists
RALEIGH. NORTH CAROLINA
A
GRIT
REMOVAL
FACILITIES
PRIMARY PE MIX
SETTLING TANKS
BASINS (4) (2)
SCREENINGS PRIMARY SOLIDS
AND GRIT PUMP STATIONS (2)
TO LANDFILL
5U I PS
ANAEROBIC
DIG ESTERS
DS
M r rry/RAIr- GAs
/2l, 700 it 3/vRr
3�1_ LFRT/o
LR
ALUM OR
ALUM
POLYMER
AERATION
ML FINAL
CU
BASINS
CLARIFIERS
B S
(8)
(C)
(4)
SUPPLEMENTAL
nod. us�v
CARBON FEED
RASE °w F
RAS
PUMP
STATIONS
DIVAS
gAA
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L WATER RECLAMATION FACILITY
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NPDES Permit NCO047597
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